Pinpoint Test BB: PSCM (Power Steering Control Module) DTC (Diagnostic Trouble Code) B1D23:4B Overheat Sensor

NOTE: Refer to Steering GSB for additional connector and wiring inspection tips.

Refer to POWER STEERING CONTROLS for schematic and connector information.

Normal Operation and Fault Conditions

Description

Description
The PSCM uses a thermistor to monitor the internal temperature of the EPAS gear. This DTC appearing by itself does not indicate a fault condition in the steering system. Diagnose all other EPAS Diagnostic Trouble Codes (DTCs) before diagnosing B1D23:4B.

Pinpoint Test Applicability

Pinpoint Test Applicability
This test applies to PSCMDTC B1D23 Overheat Sensor only. It does not apply to any other module except the PSCM.

DTC Diagnostic Strategy

DTC Diagnostic Strategy
This test inspects the steering gear and the surrounding engine compartment for hot components, missing heat shields or a damaged steering gear housing creating an opening into the steering gear.
If the module DTC list results in a large number of Diagnostic Trouble Codes (DTCs), diagnose all module hard faults first (C102D, C1B00, 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.

Diagnostic Aids

Diagnostic Aids
The PSCM reporting only DTC B1D23:4B does not indicate a fault in the PSCM. It indicates an over temperature condition due to ambient conditions or a heavy load on the EPAS system. An example of a heavy load would be multiple parking lot maneuvers over a short duration of time with low tire pressure or towing for long distances followed by multiple parking maneuvers
The thermistor used by the PSCM is calibrated for 80 deg.C (176 deg.F) and as ambient temperature decreases, so does the accuracy of the sensor. At room temperature and lower, the sensor is +/- 20 deg.C (68 deg.F).
The presence of DTC B1D23:4B prevents the active park assist system (if equipped) from activating. If set during an active park assist event, the event is terminated and the active park assist system is deactivated.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PSCM B1D23:4B	Overheat Sensor: Over Temperature	This DTC sets when the internal temperature of the EPAS gear exceeds a predetermined threshold. This is most likely due to high ambient temperature conditions, heavy loads on the steering gear, or a damaged PSCM housing allowing heat into the steering gear.

Possible Sources