Pinpoint Test BP: Abs Module Communication Concern With The GWM (Gateway Module A)

Refer to Module Communications Network for schematic and connector information.

Normal Operation and Fault Conditions

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

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 Diagnostic Trouble Codes (DTCs). This can be due to a GWM failure, a circuit failure on the 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 messages from the GWM are missing for more than 5 seconds.

Possible Causes

Network communication concern
GWM

BP1 CHECK THE COMMUNICATION NETWORK

Ignition ON.

Using a diagnostic scan tool, retrieve the DTC s from all modules.

Does the GWM pass the network test?

Yes	DIAGNOSE the GWMDTC s. REFER to: Controller Area Network (CAN) Module Communications Network . If there are no GWMDTC s, GO to BP2

No	DIAGNOSE the GWM does not communicate with the diagnostic scan tool. REFER to: Controller Area Network (CAN) Module Communications Network .

BP2 RECHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE DTC (DIAGNOSTIC TROUBLE CODE) S

Using a diagnostics scan tool, clear the ABSDTC s. Only available in the on-line OEM service information.

Put the ABS module in sleep mode by performing the following steps:
- With ALL doors closed, set the ignition from ON to OFF.
- Disconnect the diagnostic scan tool.
- Open the door, exit the vehicle and close the door.
- Wait a minimum of 90 seconds for the ABS module to enter sleep mode.

Ignition ON.

Using a diagnostic scan tool, carry out the ABS self-test. Only available in the on-line OEM service information.

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

Yes

GO to BP3

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.

BP3 CHECK FOR VOLTAGE DTC (DIAGNOSTIC TROUBLE CODE) S IN THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE
- Review the recorded DTC s from the ABS module self-test.
Is DTC U3003:16 or U3003:17 present?

Yes For DTC U3003:16, GO to Pinpoint Test A For DTC U3003:17, GO to Pinpoint Test F

No GO to BP4

BP4 RETRIEVE ALL DTC (DIAGNOSTIC TROUBLE CODE) S FROM THE GWM (GATEWAY MODULE A)
- Using a diagnostic scan tool, carry out the GWM self-test. Only available in the on-line OEM service information.
- RECORD all DTC s from the GWM self-test.
Are any DTC s present in the GWM '

Yes DIAGNOSE the GWMDTC. REFER to: Controller Area Network (CAN) Module Communications Network .

No GO to BP5

BP5 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 the GWM 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 BP6

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

BP6 CHECK FOR COMMUNICATION DTC (DIAGNOSTIC TROUBLE CODE) S IN OTHER MODULES
- Ignition ON.
- Using a diagnostic scan tool, retrieve the DTC s from all modules.
Is DTC U0146:xx set in 1 or more modules in addition to the ABS module?

Yes GO to BP7

No GO to BP8

BP7 CHECK FOR CORRECT GWM (GATEWAY MODULE A) OPERATION

Ignition OFF.

Put the ABS module in sleep mode by performing the following steps:
- With ALL doors closed, set the ignition from ON to OFF.
- Disconnect the diagnostic scan tool.
- Open the door, exit the vehicle and close the door.
- Wait a minimum of 90 seconds for the ABS module to enter sleep mode.

Disconnect GWM C2431A.

Disconnect GWM C2431C

Disconnect ABS module connector C135.

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 GWM C2431A. Make sure the connector seats and latches correctly.

Connect GWM C2431C Make sure the connector seats and latches correctly.

Connect ABS module connector C135. Make sure the connectors seat and latch correctly.

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

Is the concern still present?

Yes	CHECK OASIS for any applicable 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 GWM. REFER to: Gateway Module A (GWM) .

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.

BP8 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

Put the ABS module in sleep mode by performing the following steps:
- With ALL doors closed, set the ignition from ON to OFF.
- Disconnect the diagnostic scan tool.
- Open the door, exit the vehicle and close the door.
- Wait a minimum of 90 seconds for the ABS module to enter sleep mode.

Ignition OFF.

Disconnect ABS module connector C135.

Disconnect GWM C2431A.

Disconnect GWM C2431C

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 ABS module connector C135. Make sure the connector seats and latches correctly.

Connect GWM C2431A. Make sure the connectors seat and latch correctly.

Connect GWM C2431C Make sure the connectors seat and latch correctly.

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

Is the concern still present?

Yes	CHECK OASIS for any applicable 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 unit. REFER to: Electric Brake Booster (EBB) .

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.