Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test Cg: PSCM (Power Steering Control Module) DTC (Diagnostic Trouble Code) U0122:00 Lost Communication With Vehicle Dynamics Control Module
Refer to Wiring Diagrams POWER STEERING CONTROLS for schematic and connector information.
Normal Operation and Fault Conditions
Description
- The PSCM monitors the HS-CAN messages when the ignition has been on for more than 5 seconds, the voltage to the PSCM is greater than 10 volts and there are no Diagnostic Trouble Codes (DTCs) present inhibiting PSCM operation.
- For additional information on the messages sent to the PSCM from the VDM, REFER to: Power Steering - System Operation and Component Description .
Pinpoint Test Applicability
- This test applies to PSCMDTC U0122 Lost Communication with the VDM only. It does not apply to any other module except the PSCM.
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).
Pinpoint Test Purpose
- To verify the PSCM wiring harness and connectors are OK. This test checks the connectors and wiring from the PSCM 3 pin connector at the steering gear to the in-line connector in the engine compartment. If these circuits are working correctly, the test then directs to check the VDM and wiring harness.
Diagnostic Aids
- Do not install a new PSCM as part of the repair for a PSCMDTC U0122:00.
- DTC U0122:00 indicates a possible failure of the HS-CAN which can be due to a circuit fault in the HS-CAN, the PSCM wiring harness or a VDM concern.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Condition |
|---|---|---|
| PSCM U0122:00 | Lost Communication With Vehicle Dynamics Control Module: No Sub Type Information | This DTC sets when the PSCM does not receive the VDM messages within a certain time frame. This can occur if the VDM wiring harness or electrical connectors are loose or damaged, or if the vehicle battery state of charge levels are low. |
Possible Sources
- Fuse(s)
- Wiring, terminals or connectors
- VDM
Pinpoint Tests CG: PSCM DTC U0122 Lost Communication With The Vehicle Dynamics Control Module (VDM)
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.