Pinpoint Test Ad: Abs Module Communication Concern With The PSCM
- Normal Operation and Fault Conditions
With the ignition ON, the PSCM sends messages to the GWM over the FD-CAN3 which relays the messages to the ABS module over the FD-CAN1. 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 U0131:87 Lost Communication With Power Steering Control Module 'A': Missing Message This DTC sets when the ABS module does not receive any messages from the PSCM within the allowed time. ABS U0420:87 Invalid Data Received from Power Steering Control Module 'A': Missing Message This DTC sets when the ABS module receives messages from the PSCM, but the messages contain invalid data. Possible Causes
- Network communication concern
- PSCM
Visual Inspection and Pre-checks
- Make sure the vehicle battery state of charge is at least 80%
- Make sure the vehicle battery voltage is at least 11 VDC
- AD1 CHECK THE PSCM (POWER STEERING CONTROL MODULE) COMMUNICATION
- Ignition ON.
- Using a diagnostic scan tool, carry out the PSCM self-test. Only available in the service information
Does the PSCM communicate with the diagnostic scan tool and return DTCs '
Yes RETRIEVE and RECORD all PSCMDTCs. REFER to: Power Steering . If there are no DTCs in the PSCM, GO to AD3. No GO to AD2. - AD2 CHECK THE GWM (GATEWAY MODULE A) COMMUNICATION
- Using a diagnostic scan tool, carry out the GWM self-test. Only available in the service information
Does the GWM communicate with the diagnostic scan tool and return DTCs '
Yes RETRIEVE and RECORD all GWMDTCs. REFER to: Controller Area Network (CAN) Module Communications Network .
No DIAGNOSE the scan tool does not communicate with the GWM. REFER to: Controller Area Network (CAN) Module Communications Network . - AD3 RECHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE FOR THE LOST COMMUNICATION DTC (DIAGNOSTIC TROUBLE CODE)
- Using a diagnostic scan tool, clear the ABS module Diagnostic Trouble Codes (DTCs). Only available in the service information
- Ignition OFF.
- Ignition ON.
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NOTE: When retrieving DTCs, ignore all historical or continuous memory DTCs.
Using a diagnostic scan tool, carry out the ABS module self-test. Only available in the service information
Are any of the DTCs listed in the DTC Fault Trigger Conditions table present and active in the ABS module?
Yes GO to AD4. 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 - AD4 REVIEW THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE SELF-TEST FOR VOLTAGE-REALTED DTCS
- Review the results 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 AD5. - AD5 CHECK FOR GWM (GATEWAY MODULE A) DTCS
- Using a diagnostic scan tool, carry out the GWM self-test. Only available in the service information
Are any DTCs present and active in the GWM '
Yes RETRIEVE and RECORD all GWMDTCs. REFER to: Controller Area Network (CAN) Module Communications Network .
No GO to AD6. - AD6 CHECK FOR PSCM (POWER STEERING CONTROL MODULE) DTCS
- Using a diagnostic scan tool, carry out the PSCM self-test. Only available in the service information
Are any DTCs present and active in the PSCM '
Yes RETRIEVE and RECORD all PSCMDTCs. REFER to: Power Steering . No GO to AD7. - AD7 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN
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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 new replacement module.
- Operate the system and determine if the observable symptom is still present.
Is the observable symptom still present?
Yes GO to AD8. No The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration. -
- AD8 CHECK FOR COMMUNICATION DTCS IN OTHER MODULES
- Ignition ON.
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NOTE: When retrieving DTCs, ignore all historical or continuous memory DTCs.
Using a diagnostic scan tool, carry out a Network Test.
Is any DTC from the Fault Trigger Conditions Table set in 1 or more modules in addition to the ABS module?
Yes GO to AD9. No GO to AD10 - AD9 VERIFY PSCM (POWER STEERING CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect PSCM C1467A.
- Disconnect PSCM C1467B.
- Disconnect GWM C2451.
- Disconnect ABS Module 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 PSCM C1467A Make sure the connector seats and latches correctly.
- Connect PSCM C1467B Make sure the connector seats and latches correctly.
- Connect GWM C2451 Make sure the connector seats and latches correctly.
- Connect ABS Module C135 Make sure the connector seats and latches correctly.
- Operate the system and verify 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, DIAGNOSE the PSCM. REFER to the PSCM Symptom Chart. REFER to: Power Steering . 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. - AD10 VERIFY ABS (ANTI-LOCK BRAKE SYSTEM) OPERATION
- Ignition OFF.
- Disconnect PSCM C1467A.
- Disconnect PSCM C1467B.
- Disconnect GWM C2451.
- Disconnect ABS Module 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 PSCM C1467A Make sure the connector seats and latches correctly.
- Connect PSCM C1467B Make sure the connector seats and latches correctly.
- Connect GWM C2451 Make sure the connector seats and latches correctly.
- Connect ABS Module C135 Make sure the connector seats and latches correctly.
- Operate the system and verify 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 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.