Pinpoint Test AE: Abs Module Communication Concern With 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 .

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
ABS U0131:00	Lost Communication With Power Steering Control Module 'A': No Sub Type Information	This DTC sets when the ABS module does not receive any messages from the PSCM within the allowed time.
ABS U0420:00	Invalid Data Received from Power Steering Control Module 'A': No Sub Type Information	This DTC sets when the ABS module receives messages from the PSCM, but the messages contain invalid data.

Possible Causes

Network communication concern
GWM
PSCM

AE1 CHECK THE COMMUNICATION NETWORK
- Ignition ON.
- Clear the ABSDTCs.
- Ignition OFF.
- Ignition ON.
- Wait at least 1 minute.
- Using a diagnostic scan tool, retrieve the DTC s from the vehicle.
  NOTE: DTC s may be displayed from previous diagnostic actions.
- Using a diagnostic scan tool, carry out the Network Test.
Does the PSCM pass the network test?

Yes Diagnose any PSCMDTCs. REFER to the PSCMDTC Chart. If there are no DTC s in the PSCM GO to AE2

No REFER to: Controller Area Network (CAN) Module Communications Network .

AE2 CHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE FOR DTC (DIAGNOSTIC TROUBLE CODE) S

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.

Carry out the ABS self-test.

Is DTC s U0131:xx or U0420:xx retrieved again?

Yes

GO to AE3

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.

AE3 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 AE4

AE4 CHECK FOR PSCM (POWER STEERING CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE) S
- Ignition ON.
- Using a diagnostic scan tool, carry out the PSCM self test.
Are any PSCMDTC s present?

Yes DIAGNOSE the PSCMDTC S. REFER to: Power Steering .

No GO to AE5

AE5 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 PSCM 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 AE6

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

AE6 VERIFY MODULE CONFIGURATION
- Ignition ON.
- Using As-Built Data, configure the ABS module for trailer back up assist.
- Using As-Built Data, configure the PSCM for trailer back up assist.
- Operate the system and determine if the observable symptom is still present.
Is the concern still present?

Yes GO to AE7

No The system is operating correctly at this time. The concern may have been due to an incorrect module configuration.

AE7 CHECK FOR COMMUNICATION DTC (DIAGNOSTIC TROUBLE CODE) S IN OTHER MODULES
- Ignition ON.
- Using a diagnostic scan tool, retrieve the DTC s from the vehicle.
  NOTE: DTC s may be displayed from previous diagnostic actions.
Is DTC U0131:xx or U0420:xx set in 1 or more modules in addition to the ABS module?

Yes DIAGNOSE the PSCM. REFER to: Power Steering .

No GO to AE8

AE8 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

Ignition OFF.

Disconnect ABS module C135 .

Disconnect ABS module C1463A .

Disconnect ABS module C1463B .

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 C135 . Make sure the connector seats and latches correctly.

Connect ABS module C1463B . Make sure the connector seats and latches correctly.

Connect ABS module C1463A . 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) .

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.