Lincoln Navigator: Anti-Lock Brake System (ABS) and Stability Control / Anti-Lock Brake System (ABS) and Stability Control. Diagnosis and Testing

Normal Operation and Fault Conditions

If DTC U0140:00 or U0422:00 is present with U300A:29, diagnose the lost communication DTC first.

The ABS module, hydraulic pump and solenoid valves require an operating voltage between 10 and 17 volts. The parking brake system requires an operating voltage of 9 volts or higher. The ABS module receives this voltage from the BJB . The ABS module has 2 ground circuits. Excessive resistance or an open in one or more of these circuits, a discharged battery or a inoperative charging system results in the ABS module setting a DTC .

DTC Fault Trigger Conditions

Possible Sources

• Fuse(s)
• Wiring, terminals or connectors
• Charging system concern
• 12-volt Battery
• EBB unit

Visual Inspection and Pre-checks

• Make sure the vehicle battery terminals and cables are free of any corrosion and other contaminants.
• Make sure the vehicle battery terminals are tightened to their correct torque specifications.
• Make sure all EBB or ABS module fuses in the BJB are OK.

Normal Operation and Fault Conditions

With the ignition ON, the HVAC control module sends messages to the GWM over the MS-CAN , The GWM relays these messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a HVAC control module failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the HVAC control module,REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• HVAC control module

Normal Operation and Fault Conditions

With the ignition ON, the GWM sends messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a GWM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the GWM , refer to the Network Message Chart in Section 206-09, Description and Operation in the Workshop Manual.

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM

Normal Operation and Fault Conditions

With the ignition ON, the BCM sends messages to the GWM over the HS-CAN1 . The GWM relays these message to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a BCM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the BCM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• BCM

NOTE: If equipped, MyKey allows users to configure traction control to be either always on or selectable. If a MyKey restricted key is in use with the MyKey traction control feature configured to always on, traction control cannot be disabled. An admin key must be used to enable and disable traction control.

NOTE: This test requires the use of at least 2 ignition keys (passive or IKT ) programmed to the vehicle; one admin ignition key and one restricted ignition key.

Normal Operation and Fault Conditions

The stability-traction control disabled indicator (sliding car OFF icon) in the IPC provides traction control system status to the driver. When the driver deactivates the traction control, the APIM sends a message to the IPC over the HS-CAN3 . The IPC then sends a message to the GWM over the HS-CAN3 indicating the driver has requested the traction control to be disabled. The GWM relays this message to the ABS module over the FD-CAN . The ABS module continues to monitor for excessive wheel spin, but no longer takes any action when a traction event is detected.

After receiving the traction control status message from the IPC , the ABS module then sends a message to the GWM over the FD-CAN to illuminate the stability-traction control disabled indicator (sliding car OFF icon). The GWM relays this message to the IPC over the HS-CAN3 . The IPC responds by illuminating the stability-traction control disabled indicator (sliding car OFF icon). The traction control system remains deactivated until the driver changes the traction control state in the message center or until the ignition is cycled.

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• IPC

Normal Operation and Fault Conditions

The ABS module may set an over-voltage DTC if the vehicle has been recently jump started, the battery has been recently charged or the battery has been discharged. The battery may become discharged due to excessive load(s) on the charging system from aftermarket accessories or if the battery has been left unattended with the accessories on.

The ABS module, hydraulic pump and solenoid valves require an operating voltage between 10 and 17 volts. The parking brake system requires an operating voltage of 9 volts or higher. The ABS module receives this voltage from the BJB . The ABS module has 2 ground circuits.

DTC Fault Trigger Conditions

Possible Sources

• Charging system concern
• EBB unit (vehicles with electric boost)
• ABS module (vehicles with vacuum boost)

Normal Operation and Fault Conditions

The ABS module incorporates a function for testing the vehicle on a dynamometer to prevent wheel speed sensor Diagnostic Trouble Codes (DTCs) from setting during testing. The PCM sends a message to the ABS module when the vehicle is setup for testing. When the ABS module receives this message it knows to ignore discrepancies between the front and rear wheel speed sensors.

The ABS module exits the test mode automatically when the PCM sends the exit message, the ignition is set to OFF, either of the non-driven wheels exceeds 20 km/h (12 mph) or a wheel speed sensor DTC is detected on any wheel speed sensor.

REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• ABS module in test mode

Visual Inspection and Pre-checks

• Drive the vehicle above 20 km/h (12 mph). Stop and cycle the ignition from ON to OFF and back to ON. Carry out the ABS module self-test. If the DTC returns, retrieve and diagnose all PCM Diagnostic Trouble Codes (DTCs).

Normal Operation and Fault Conditions

REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Brake system has not been bled

• Ignition ON.

• Using a diagnostic scan tool, carry out the ABS module self-test.

Normal Operation and Fault Conditions

The EBB contains several hydraulic valves, hydraulic pressure sensors, a linear actuator and a pump motor. These components work in conjunction to provide the force necessary to bring the vehicle to a stop. The ABS module monitors these components for internal faults. If a fault occurs which impacts the base braking system, the ABS module sets one or more Diagnostic Trouble Codes (DTCs) and illuminates the red brake warning indicator.

DTC Fault Trigger Conditions

Possible Sources

• Air trapped in the hydraulic system
• External brake system leak
• Internal EBB unit leak
• EBB unit internal failure

Normal Operation and Fault Conditions

The BCM is programmed with vehicle tire size information during the module configuration step. The BCM shares tire size information with other module over the HS-CAN1 through the GWM . When this DTC sets, the ABS module sends a message to the IPC to illuminate the ABS warning indicator.

DTC Fault Trigger Conditions

Possible Sources

• Temporary or mini-spare tire in use
• Under inflated tires
• Mismatched sized wheels and tires
• Network communication concern
• Incorrect BCM configuration

Normal Operation and Fault Conditions

The selectable drive mode switch is part of the ATCM . When the drive mode switch is activated, the ATCM sends a message to the GWM over the HS-CAN2 . The GWM relays the message to the ABS module over the FD-CAN . If the ABS module does not receive any messages within a certain time frame (usually less than 1 second) or if the message contains invalid information, the ABS module sets a DTC . For information on the all messages sent to the ABS module by the ATCM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

The auto hold switch is used to activate and deactivate the auto hold feature. The switch is an internal component of the ATCM . When the driver presses the auto hold switch, the ATCM sends an auto hold switch message to the GWM over the HS-CAN2 . The GWM relays the message to the ABS module over the FD-CAN . The ABS module then waits for messages from the RCM and BCM as well as ABS sensor information to indicate the auto hold feature can be activated. Once all criteria has been met, the ABS module activates the auto hold feature.

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• ATCM

Normal Operation and Fault Conditions

The brake fluid level switch is hardwired to the ABS module, the module monitors the switch and brake fluid level. If a circuit fault or fluid loss is detected, a DTC is set.

REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Wiring, terminals or connectors
• Leak in the hydraulic system
• Brake fluid level switch
• EBB unit

• Ignition ON.

• Using a diagnostic scan tool, retrieve all ABS module Diagnostic Trouble Codes (DTCs).

• Note all ABS module Diagnostic Trouble Codes (DTCs).

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

Normal Operation and Fault Conditions

Active wheel speed sensors generate a voltage signal proportional to wheel speed which is sent to the ABS module. Each wheel speed sensor is connected to the ABS module through 2 wires and a connector at each wheel speed sensor. The 2 circuits provide both sensor power and sensor signal return. When the ignition mode is set to ON, the ABS module carries out a self-test by sending a reference voltage through the wheel speed sensors and their circuitry.

DTC Fault Trigger Conditions

Possible Sources

• Wiring, terminals or connectors
• Wheel speed sensor
• EBB unit (vehicles with electric boost)
• ABS module (vehicles with vacuum boost)

Visual Inspection and Pre-checks

• Make sure the wheel speed sensor harness is routed correctly and is undamaged.
• Make sure the wheel speed sensor electrical connector is free from any corrosion or other contaminants.

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

Normal Operation and Fault Conditions

Active wheel speed sensors generate a voltage signal proportional to wheel speed which is sent to the ABS module. Each wheel speed sensor is connected to the ABS module through 2 wires and a connector at each wheel speed sensor. The 2 circuits provide both sensor power and sensor signal return. When the ignition mode is set to ON, the ABS module carries out a self-test by sending a reference voltage through the wheel speed sensors and their circuitry.

DTC Fault Trigger Conditions

Possible Sources

• Wiring, terminals or connectors
• Wheel speed sensor
• EBB unit (vehicles with electric boost)
• ABS module (vehicles with vacuum boost)

Visual Inspection and Pre-checks

• Make sure the wheel speed sensor harness is routed correctly and is undamaged.
• Make sure the wheel speed sensor electrical connector is free from any corrosion or other contaminants.

Normal Operation and Fault Conditions

The hill start assist feature is configured in the IPC . The IPC sends the hill start configuration information in a message during module wake up (ignition ON). The hill start feature cannot be turned on and off. If the hill start assist feature is inoperative, then the IPC has not been correctly configured or there is a network communication error.

Verify the IPC has been configured correctly. REFER to: Module Configuration - System Operation and Component Description (418-01A Module Configuration, Description and Operation).

Retrieve and diagnose all communication Diagnostic Trouble Codes (DTCs) from the IPC . REFER to: Instrument Panel Cluster (IPC) - System Operation and Component Description (413-01 Instrumentation, Message Center and Warning Chimes, Description and Operation).

Possible Sources

• Network communication concern
• IPC concern

Normal Operation and Fault Conditions

The ABS module and BCM share a secret code (target identifier) when the ignition is set to ON. This code is generated during the PATS programming procedure. If either a new BCM or a new ABS module has been installed, the PATS programming procedure must be carried out.

REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• BCM programming error
• ABS module programming error

Visual Inspection and Pre-checks

• Check the vehicle repair history and determine if a new BCM or ABS module has been installed. If a new module has been installed, verify it has been programmed correctly and verify the PATS Module Initialization has been carried out using the FDRS Scan Tool PATS Application.

Normal Operation and Fault Conditions

The steering wheel rotation sensor sends steering wheel rotation speed, angle and direction of rotation to the SCCM . The SCCM sends this information to the GWM over the HS-CAN2 , which relays the information to the ABS module over the FD-CAN . A failure of either CAN , the SCCM or the internal sensor causes the ABS module to set one or more Diagnostic Trouble Codes (DTCs).

REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Incorrectly mounted RCM
• Network communication concern
• Incomplete or incorrect stability control sensor calibration
• Mismatched wheels and tires
• Loose or worn suspension components
• Loose or worn steering components
• Steering wheel rotation sensor
• Incorrectly installed SCCM
• Incorrectly installed clockspring
• SCCM

Normal Operation and Fault Conditions

The CCM communicates with the IPMA over a private CAN . The IPMA sends the CCM messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a CCM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the CCM and IPMA , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• CCM

Normal Operation and Fault Conditions

The TBM module may also be known as the TRM .

With the ignition ON, the TBM sends messages to the GWM over the HS-CAN3 . The GWM relays these messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a TBM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the TRM TBM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• TRM

Normal Operation and Fault Conditions

This DTC is for informational purposes only and sets in conjunction with other ABS module Diagnostic Trouble Codes (DTCs). Retrieve and diagnose all other ABS module Diagnostic Trouble Codes (DTCs).

DTC Fault Trigger Conditions

Possible Sources

• Low battery voltage
• Open circuit or fuse

Normal Operation and Fault Conditions

The ABS module monitors all base brake, anti-lock brake, traction control and stability control functions and features. If a system error occurs which could cause irreparable damage to the system, the ABS module disables the EBB unit. The base brake system still functions, but there is no brake boost assist. This can also occur if the EBB unit loses power or ground.

System over-voltage combined with other specific circumstances may cause the EBB unit to provide excessive brake assist or a "touchy" pedal, where the brakes apply heavily with a light application of the brake pedal.

In either of these cases, no brake assist or too much brake assist, the ABS module sets Diagnostic Trouble Codes (DTCs) indicating possible concerns.

Possible Sources

• Diagnostic Trouble Codes (DTCs) preset in the ABS module

Visual Inspection and Pre-checks

• Retrieve and diagnose all ABS module Diagnostic Trouble Codes (DTCs)

Normal Operation and Fault Conditions

With the ignition ON, the DCMR sends messages to the GWM over the HS-CAN1 . The GWM relays these messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a DCMR failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the DCMR , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• DCMR

• Ignition ON.

• NOTE: Diagnostic Trouble Codes (DTCs) may be displayed from previous diagnostic actions. Using a diagnostic scan tool, carry out the Network Test.

• Review the results of the modules communicating on the network from the previous step.

• Using a diagnostic scan tool, clear the ABS module Diagnostic Trouble Codes (DTCs).

• Ignition OFF.

• Ignition ON.

• Using a diagnostic scan tool, carry out the ABS module self-test.

• Retrieve and record all ABS module Diagnostic Trouble Codes (DTCs).

• Review the ABS module Diagnostic Trouble Codes (DTCs) retrieved in the previous step.

• Using a diagnostic scan tool, carry out the GWM self-test.

• Using a diagnostic scan tool, carry out the DCMR self-test.

NOTE: If new modules were installed prior to the DTC being set, the module configuration can be incorrectly set during the PMI or the PMI may not have been carried out.

• Check the vehicle service history for recent service actions related to the DCMR or the ABS module. If recent service history is found:
  • Verify the correct replacement module was installed. HVBOM may be used to verify correct part fitment.
  • Verify the configuration of replacement module was correct. Re-configure the module using as-built data if prior configuration is suspect.
  • Verify the module was not obtained from a like vehicle and installed into customer vehicle. Return the swapped module to source vehicle and obtain new replacement module.

• Operate the system and determine if the observable symptom is still present.

• Ignition ON.

• Using a diagnostic scan tool, carry out the Network Test.

• Ignition OFF.

• Disconnect all DCMR electrical connectors.

• Disconnect all ABS module electrical connectors.

• Disconnect all GWM electrical connectors.

• Using a good light source, inspect all disconnected electrical connectors for the following:
  • corrosion - install new connector or terminal and clean the module pins
  • damaged or bent pins - install new terminals or pins
  • pushed-out pins - install new pins as necessary
  • spread terminals - install new terminals as necessary

• Connect all GWM electrical connectors. Make sure the connectors seat and latch correctly.

• Connect all ABS module electrical connectors. Make sure the connectors seat and latch correctly.

• Connect all DCMR electrical connectors. Make sure the connectors seat and latch correctly.

• Operate the system and verify the concern is still present.

• Ignition OFF.

• Disconnect all DCMR electrical connectors.

• Disconnect all ABS module electrical connectors.

• Disconnect all GWM electrical connectors.

• Using a good light source, inspect all disconnected electrical connectors for the following:
  • corrosion - install new connector or terminal and clean the module pins
  • damaged or bent pins - install new terminals or pins
  • pushed-out pins - install new pins as necessary
  • spread terminals - install new terminals as necessary

• Connect all GWM electrical connectors. Make sure the connectors seat and latch correctly.

• Connect all ABS module electrical connectors. Make sure the connectors seat and latch correctly.

• Connect all DCMR electrical connectors. Make sure the connectors seat and latch correctly.

• Operate the system and verify the concern is still present.

Normal Operation and Fault Conditions

The ABS module uses several sensors (wheel speed, steering wheel rotation, stability control) to determine if ABS or stability control intervention is required. Accurate sensor readings rely on the vehicle being in good operational condition with as few mechanical and electrical concerns as possible. In addition, the wheels and tires must be within vehicle manufacturer's specifications as described on the VC label and the base brake system and parking brake system must be in good operational condition. If one or more of these items or systems are in need or repair or are not working at full capacity, the ABS or stability control system may activate when the driving condition does not warrant activation.

Possible Sources

• Wheels
• Tires
• Suspension components
• Parking brake dragging
• PSCM
• RCM

Normal Operation and Fault Conditions

The ABS module continually monitors the status and condition of the ABS and stability control systems. Using the various sensor inputs, the ABS module is able to calculate the brake system temperature. Excessive brake system temperatures can lead to a brake fade condition. If the ABS module determines the brake system is overheated, a DTC is set and the ABS warning indicator is illuminated.

REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Parking brake partially applied
• Brake caliper concern

Visual Inspection and Pre-checks

• Inspect all 4 wheel ends for issues causing brake drag and repair as necessary.

Normal Operation and Fault Conditions

The ABS module carries out self tests during operation, the module also monitors various inputs and compares the values to what is expected. If the values received are out of range, are not what is expected, or if any of the self tests fail, the ABS module sets a DTC .

REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

The U3000:XX Diagnostic Trouble Codes (DTCs) may set along with other ABS Diagnostic Trouble Codes (DTCs). Diagnose all other ABS module Diagnostic Trouble Codes (DTCs) before diagnosing any ABS module U3000:XX Diagnostic Trouble Codes (DTCs).

DTC Fault Trigger Conditions

Possible Sources

• Incorrect sensor input
• Stuck valve
• EBB unit

Normal Operation and Fault Conditions

During new module installation, configuration files are loaded into the new module being replaced. If a discrepancy is detected between the modules or an incomplete programming procedure is carried out, a DTC is set.

DTC Fault Trigger Conditions

Possible Sources

• Incomplete programming procedure
• Improper programming procedure
• EBB unit

Normal Operation and Fault Conditions

With the ignition ON, the VDM sends messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a VDM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the VDM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• VDM

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

Normal Operation and Fault Conditions

The wheel speed sensor uses the tone ring to generate a square wave signal proportional to wheel speed which is sent to the ABS module. The front wheel bearing, rear axle shafts, tone rings and wheel speed sensors must be undamaged and free from any contamination to produce a clean signal for use by the ABS module. Also, all 4 tires and wheels must be of the same manufacturer recommended size for the wheel speed sensor to generate an accurate wheel speed signal.

DTC Fault Trigger Conditions

Possible Sources

• Tire Pressure
• Incorrect or mismatched tire
• Wheel speed sensor encoder contamination
• Wiring, terminals or connectors
• Wheel bearing
• Wheel speed sensor encoder ring
• Wheel speed sensor
• EBB unit (vehicles with electric boost)
• ABS module (vehicles with vacuum boost)

Normal Operation and Fault Conditions

With the ignition ON, the IPMA sends messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the IPMA , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• IPMA

Normal Operation and Fault Conditions

The ABS module uses information from the wheel speed sensors, RCM and PSCM to determine when stability control intervention is necessary to help stabilize the vehicle. The ABS module uses the EBB unit to modulate the brake fluid pressure to the brake calipers and continues to monitor the sensor and module input until the instability event has been corrected. Once the sensors and modules indicate the instability event has been corrected, the ABS module deactivates the EBB unit. Under inflated tires, wheels and tires that do not match VC label specifications, suspension and steering damage, and one or more sensor failures contribute to the ABS module setting this DTC .

DTC Fault Trigger Conditions

Possible Sources

• Tire pressure
• Wiring, terminals or connectors
• Chassis damage
• Steering damage or alignment
• Wheel speed sensor
• RCM
• PSCM

Normal Operation and Fault Conditions

With the ignition ON, the PSCM sends messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a PSCM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the PSCM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• PSCM

Normal Operation and Fault Conditions

When the ignition is set to ON, the ABS module and the BCM share VIN information through the GWM over the HS-CAN1 and FD-CAN .

When a new EBB unit or ABS module is installed, the ABS module must be programmed with the vehicle information. REFER to: Module Configuration - System Operation and Component Description (418-01A Module Configuration, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• BCM configuration
• ABS module configuration

Normal Operation and Fault Conditions

The ABS module receives vehicle yaw rate, lateral acceleration, longitudinal acceleration and roll rate from RCM over the HS-CAN2 , through the GWM . The yaw rate sensor, lateral accelerometer, longitudinal accelerometer and roll rate sensor are all contained in the RCM . A failure of the HS-CAN2 , an internal failure of the RCM or the internal sensors causes the ABS module to set one or more Diagnostic Trouble Codes (DTCs).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• Incorrectly installed RCM
• RCM

Normal Operation and Fault Conditions

With the ignition ON, the SCCM sends messages to the GWM over the HS-CAN2 . The GWM relays these messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a SCCM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the SCCM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• SCCM

Normal Operation and Fault Conditions

With the ignition ON, the PCM sends messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a PCM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the PCM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

The TCM is an internal component of the PCM .

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• PCM

Normal Operation and Fault Conditions

With the ignition in RUN, the ABS module continuously monitors the base brake system, the ABS , and the stability control system. If there is a concern present in one of the systems, the ABS module sets a DTC and sends a message to the GWM over the FD-CAN , the GWM relays this message to the IPC . Once the message is received, the IPC illuminates the appropriate warning indicator.

The IPC also illuminates the warning indicators as part of a self test when the ignition is set to RUN or ACC. REFER to: Instrument Panel Cluster (IPC) - System Operation and Component Description (413-01 Instrumentation, Message Center and Warning Chimes, Description and Operation).

Possible Sources

• Diagnostic Trouble Codes (DTCs) present in the ABS module
• Low brake fluid
• Brake fluid level sensor
• ABS or stability control concern
• IPC concern

Visual Inspection and Pre-checks

• Check for ABS module Diagnostic Trouble Codes (DTCs), if there are no Diagnostic Trouble Codes (DTCs) present, refer to Section 413-01 to diagnose the IPC warning indicators.

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

NOTE: This pinpoint test only applies to vehicles with an Electric Brake Booster (EBB) unit.

Normal Operation and Fault Conditions

The brake pedal switch is an internal component of the EBB unit and cannot be serviced separately.

When the brake pedal is pressed, the ABS module sends a signal to the PCM along 2 hardwired circuits, the ABS module also sends out brake pedal position and pressure messages on the CAN . The ABS module monitors both brake pedal output circuits, if a circuit fault is detected such as a short to ground or an open circuit, a DTC is set. REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Wiring, terminals or connectors
• EBB unit

Normal Operation and Fault Conditions

Vehicles equipped with EPB are also equipped with an auto hold feature. This feature must be enabled by the driver by pressing the auto hold switch once the driver seatbelt is buckled and the driver door is closed.

Pressing the auto hold switch enables the auto hold feature, but does not activate auto hold. When the switch is pressed, the module sends a message to the ABS module indicating the system has been enabled. The ABS module then waits for messages from the RCM and BCM as well as ABS sensor information to indicate the auto hold feature can be activated. Once all criteria has been met, the ABS module activates the auto hold feature.

In the case of a system error, the instrument cluster displays messages and icons.

Possible Sources

• Network communication concern
• HVAC module concern
• ABS module

Normal Operation and Fault Conditions

The ABS module monitors various inputs and compares the values to what should be expected. If the values received are out of range or not what should be expected, the ABS module sets a DTC .

DTC Fault Trigger Conditions

Possible Sources

• Incorrect sensor input
• Air trapped in the hydraulic system
• EBB unit

Normal Operation and Fault Conditions

The ABS module monitors various inputs and compares the values to what should be expected. If the values received are out of range or not what is expected, the ABS module sets a DTC . When a new ABS module or RCM is installed, the stability control sensors in the RCM must be initialized. This is accomplished using a diagnostic scan tool to run the ABS Calibration routine.

DTC Fault Trigger Conditions

Possible Sources

• ABS Calibration routine not carried out
• RCM concern
• EBB unit

Normal Operation and Fault Conditions

With the ignition ON, the APIM sends messages to the GWM over the HS-CAN3 . The GWM relays these messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a APIM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the APIM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• APIM

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

Normal Operation and Fault Conditions

The EBB unit uses a motor to pressurize the brake system and to operate the ABS , ESC , RSC and other stability control features. The ABS module monitors the motor performance and sets a DTC when a motor fault is detected.

DTC Fault Trigger Conditions

Possible Sources

• Fuses
• Wiring, terminals or connectors
• EBB unit

Normal Operation and Fault Conditions

The CCM communicates with the IPMA over a private CAN . The IPMA sends the CCM messages to the GWM over the HS-CAN2 . The GWM relays these messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a CCM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the CCM and IPMA , refer to the Network Message Chart in Section 206-09, Description and Operation in the Workshop Manual.

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• CCM

Normal Operation and Fault Conditions

With the ignition ON, the IPC sends messages to the GWM over the HS-CAN3 . The GWM relays these messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a IPC failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the IPC , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

When the driver activates or deactivates the hill descent control system through the message center, the APIM sends a hill descent control message to the IPC over the HS-CAN3 . The IPC then sends a message over the HS-CAN3 to the GWM which relays the hill descent message to the ABS mode over the FD-CAN . When the IPC receives the message, the module illuminates the hill descent control indicator. The ABS module takes the necessary action depending on the switch inputs and hill descent control message.

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GWM
• IPC

Normal Operation and Fault Conditions

With the ignition in RUN, the ABS module continuously monitors the base brake system, the ABS , and the stability control system. If there is a concern present in one of the systems, the ABS module sets a DTC and sends a message to the GWM over the FD-CAN , the GWM relays this message to the IPC . Once the message is received, the IPC illuminates the appropriate warning indicator.

The IPC also illuminates the warning indicators as part of a self test when the ignition is set to RUN or ACC. REFER to: Instrument Panel Cluster (IPC) - System Operation and Component Description (413-01 Instrumentation, Message Center and Warning Chimes, Description and Operation).

Possible Sources

• Diagnostic Trouble Codes (DTCs) present in the ABS module
• Low brake fluid
• Brake fluid level sensor
• ABS or stability control concern
• IPC concern

Visual Inspection and Pre-checks

• Check for ABS module Diagnostic Trouble Codes (DTCs), if there are no Diagnostic Trouble Codes (DTCs) present, diagnose the IPC warning indicators.

Normal Operation and Fault Conditions

With the ignition ON, the diagnostic scan tool communicates with the ABS module over the FD-CAN . Communications can be interrupted by a wiring condition such as a short to ground, a short to voltage or an open circuit; module failure is also a cause of no communication.

Possible Sources

• Fuses
• Wiring, terminals or connectors
• ABS module

• Diagnostics in Workshop Manual Section 418-00 MUST BE CARRIED OUT before continuing with this pinpoint test.

Normal Operation and Fault Conditions

The AWD module may also be known as the TCCM .

With the ignition ON, the AWD module sends messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a AWD module failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the AWD module, REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• AWD module

Normal Operation and Fault Conditions

With the ignition ON, the GSM sends messages to the ABS module over the FD-CAN . If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC . This can be due to a GSM failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the GSM , REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description (206-09 Anti-Lock Brake System (ABS) and Stability Control, Description and Operation).

DTC Fault Trigger Conditions

Possible Sources

• Network communication concern
• GSM