Pinpoint Test Cd: PSCM (Power Steering Control Module) DTC (Diagnostic Trouble Code) U0554:00 Invalid Data Received From The Accessory Protocol Interface Module

Refer to POWER STEERING CONTROLS for schematic and connector information.

Normal Operation and Fault Conditions

Description

Description
The PSCM monitors the HS-CAN when the voltage to the PSCM is greater than 10 volts and there are no Diagnostic Trouble Codes (DTCs) present inhibiting PSCM operation.

Pinpoint Test Applicability

Pinpoint Test Applicability
This test applies to PSCMDTC U0554 Invalid Data Received from the APIM only. It does not apply to any other module except the PSCM.

DTC Diagnostic Strategy

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

Pinpoint Test Purpose
To direct the diagnosis to the module and associated circuit sending the faulty or unknown information in the messages.

Diagnostic Aids

Diagnostic Aids
For additional information on the messages sent to the PSCM from the APIM module, refer to the Network Message List in the Power Steering article.
DTC U0554:00 indicates a concern with the lane information sent from the APIM. The module reporting this DTC is not the problem module. Do not install a new PSCM as part of the repair for PSCMDTC U0554:00.
The presence of DTC U0554:00 may prevent the trailer backup optional feature from activating. If the DTC sets during an backup event, the event may be terminated and the feature may be deactivated.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PSCM U0554:00	Invalid Data Received From Accessory Protocol Interface Module: No Sub Type Information	This DTC is set if the PSCM receives an "fault" or "unknown" message from the APIM instead of valid information.

Possible Sources

HS-CAN concern
APIM
This DTC sets when the PSCM does not receive the APIM messages within a certain time frame. This can occur if the APIM wiring harness or electrical connectors are loose or damaged, or if the vehicle battery state of charge levels are low. Consult the DTC Index for additional information if needed.