Pinpoint Test Aa: Abs (Anti-Lock Brake System) Module Communication Concern With GWM (Gateway Module A)

Refer to Horn/Cigar Lighter for schematic and connector information.

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 a certain time frame (usually less than 1 second), the ABS module sets DTC s. This can be due to a GWM failure, a circuit failure on the FD-CAN or an excessive load on the network.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
ABS U0146:00	Lost Communication With Serial Data Gateway 'A': No Sub Type Information	This DTC sets in the ABS module if the IPC messages from the GWM are missing for more than 5 seconds.

Possible Causes

Network communication concern
Wiring, terminals or connectors
GWM
ABS module

AA1 CHECK THE COMMUNICATION NETWORK

Ignition ON.

Clear the ABSDTC s.

Ignition OFF.

Ignition ON.

Wait at least 1 minute.

Using a diagnostic scan tool, RETRIEVE DTC s from the vehicle.
NOTE: DTC s may be displayed from previous diagnostic actions.

Does theGWM pass the network test?

Yes	RETRIEVE and RECORD all GWMDTC s. REFER to the SASMDTC Chart.If there are no DTC s in the GWM GO to AA2

No	REFER to: Controller Area Network (CAN) Module Communications Network - System Operation and Component Description to diagnose the module not responding to the scan tool.

AA2 CHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE FOR DTC (DIAGNOSTIC TROUBLE CODE) S

Ignition OFF.

Ignition ON.

Carry out the ABS self-test.

Are any of the DTC s listed in the Fault Setting Conditions Table retrieved again?

Yes

GO to AA3

No	The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition

AA3 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN

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 theGWM 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 a new replacement module.

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

Is the observable symptom still present?

Yes

GO to AA4

No	The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

AA4 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

Ignition OFF.

Disconnect ABS Module connector, C1990.

Using a good light source, INSPECT the electrical connector 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 ABS Module connector, C1990. Make sure the connector seats and latches correctly..

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes	CHECK OASIS for any service articles: TSB, GSB, SSM or FSA.If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions.If no service articles address this concern, INSTALL a new EBB module. REFER to: Electric Brake Booster (EBB) - LHD 4WD/LHD RWD

No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.