Pinpoint Test A: DTC (Diagnostic Trouble Code) U0131:XX Lost Communication With The PSCM (Power Steering Control Module), Or The PSCM (Power Steering Control Module) Cannot Communicate With The Diagnostic Scan Tool Or Open PSCM (Power Steering Control Module) Fuse
NOTE:
Refer to Steering GSB for additional connector and wiring inspection tips.
Refer to POWER STEERING CONTROLS Wiring Diagrams for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Power Steering - System Operation and Component Description .
- Description
- There are 2 power sources for the PSCM, the high current power steering fuse, and the low current power steering fuse. Refer to the wiring diagrams to review the PSCM circuit for both the high current and low current fuse locations as well as the associated power and ground wiring. Open power steering fuse can occur when the power or ground wiring is shorted against another component or water intrusion in the respective connectors or connections.
- Pinpoint Test Applicability
- This test applies to the following diagnostic concerns:
- DTC U0131 set in a module other than the PSCM
- The symptom "PSCM Does Not Communicate With The Diagnostic Scan Tool"
- The symptom "Open PSCM Fuse(s)"
This test DOES NOT apply to any other DTC or symptom.
- DTC Diagnostic Strategy
- If the module DTC list results in a large number of Diagnostic Trouble Codes (DTCs), diagnose all module hard faults first (C102D, C1B00, C200B, C200C, C200D, U2011 and U3000) before diagnosing any network faults (lost communication or invalid data). If voltage concern Diagnostic Trouble Codes (DTCs) are present, diagnose those after any module hard faults and before any network faults. Diagnose all current and active Diagnostic Trouble Codes (DTCs) before diagnosing any historic Diagnostic Trouble Codes (DTCs).
- This DTC sets in other modules when those modules do not receive messages from the PSCM within a certain time limit. This can occur if the vehicle wiring harness wires or connections, connectors or pins between the PSCM and other modules are loose or damaged. This DTC also sets if the PSCM is not communicating on the vehicle CAN due to an internal fault condition or a low battery state of charge. Consult the Possible Causes list for additional information.
- Pinpoint Test Purpose
- To verify the PSCM, wiring harness, and connections are working correctly. This test also verifies the existence of a low battery state of charge.
Possible Sources
- Fuse(s)
- Wiring, terminals or connectors
- HS-CAN concern
- PSCM
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 BJB and high-current BJB fuses related to the PSCM are OK.
NOTE:
Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
NOTE:
Service Information diagnostics for another module not communicating with the PSCM must be carried out prior to entering this test. REFER to GENERAL INFORMATION
for an index of all DTC charts and follow the diagnostics for the DTCs present.