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PSCM




DTC C0895 (PSCM)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptors
DTC C0895 03
- Device Voltage Below Threshold - PSCM 42V

DTC C0895 07
- Device Voltage Above Threshold - PSCM 42V

DTC C0895 12
- Device Voltage Below Minimum Threshold - PSCM 42V

Diagnostic Fault Information





Typical Scan Tool Data













Circuit/System Description

The accessory DC power control module (APM) supplies 42 volts to the power steering control module (PSCM). The PSCM monitors the supplied intermediate voltage to determine if it is within a valid operating range. Damage to components, and incorrect data may occur if the voltage is out of range. The PSCM disables power assist and sets DTC C0895 if high or low intermediate voltage is detected.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

C0895 03

Intermediate voltage is less than 40 volts.

C0895 07

Intermediate voltage is greater than 60 volts.

C0895 12

Intermediate voltage is less than 26 volts.

Action Taken When the DTC Sets

* The driver information center (DIC) displays the SERVICE POWER STEERING warning message.
* The PSCM limits the amount of steering assist if DTC C0895 03 is set.
* The PSCM disables steering assist if DTC C0895 07 or 12 is set.

Conditions for Clearing the DTC

* The DTC will pass when the intermediate voltage returns to the normal range.
* A history DTC will clear if the condition does not return after 100 consecutive ignition cycles.

Diagnostic Aids

* DTC C0895 will set if the APM has disabled the 42-volt conversion for any reason, such as a drive motor DTC. Diagnose any DTCs in the APM that disable the 42-volt circuit before diagnosing DTC C0895.
* DTC C0895 may set if the engine stalls. Diagnose any engine stall DTCs in the ECM before diagnosing DTC C0895.
* DTC C0895 may set if the serial data is interrupted. Verify that all modules can communicate, and diagnose any U-codes before diagnosing DTC C0895.
* The APM may disable the 42-volt conversion if the 12-volt battery has low voltage. The PSCM will set DTC C0895 as a result. Verify that the 12-volt battery is fully charged before diagnosing DTC C0895.
* If there is low voltage on the 42-volt circuit only when turning the steering wheel, the power steering motor is drawing too much current. This condition may set DTC C0895.
* As the front wheels roll over bumps while driving, the power steering motor will generate voltage spikes on the 42V circuit. The PSCM contains a zener diode, to suppress any voltage spikes greater than 50 volts. The scan tool PSCM Intermediate Voltage parameter does not update fast enough to view most voltage spikes. The scan tool APM 42V Circuit Maximum parameter will record and display the maximum voltage on the 42V circuit during the current ignition cycle, including the voltage spikes caused by bump-steer. If the scan tool APM 42V Circuit Maximum parameter is greater than 50 volts after driving on a bumpy road, then the diode in the PSCM is open. This condition may set DTC C0895.
* When testing for voltage at the APM 42V connector X2, use care not to cause a short between the 42V+ terminal 2 and the grounded shield which surrounds it. Use only the approved terminal probe, with the heat-shrink insulation in good condition, and only connect or disconnect the terminal probe when the 42-volt circuit is OFF. Test the terminals on the APM itself, not the harness. Do not touch the DMM or test leads while the ignition is ON.

Reference Information
Schematic Reference

Power Steering Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

* Power Steering System Description and Operation (Hydraulic Power Steering) (Power Steering System Description and Operation (Hydraulic Power Steering))Power Steering System Description and Operation (EPS) (Power Steering System Description and Operation (EPS))
* Charging System Description and Operation (Description and Operation)

Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

EL-48900 HEV Safety Kit

Circuit/System Verification

1. Verify that there are no DTCs in the APM that disable the 42-volt circuit, no engine-stall DTCs in the ECM, and no U-codes in any module.

• If there are any of the specified DTCs, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

2. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6-15.0 volts.

• If not within the specified range, refer to Charging System Test (Charging System Test).

3. Engine running, observe the scan tool PSCM Intermediate Voltage parameter. The voltage should be 37.5-50 volts.

• If not within the specified range, refer to Voltage Out Of Range At All Times.

4. Engine running, rotate the steering wheel left and right while stationary. Observe the scan tool PSCM Intermediate Voltage parameter. The voltage should remain greater than 37.5 volts.

• If the voltage is less than the specified range only when turning the steering wheel, refer to Low Voltage When Turning.

5. Operate the vehicle on a bumpy road. Observe the scan tool APM 42V Circuit Maximum parameter. The scan tool 42V Circuit Maximum parameter should be less than 50 volts.

• If the voltage is greater than the specified range, replace the PSCM.

Circuit/System Testing
Voltage Out Of Range At All Times

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

* Identify how to test for the presence of high voltage.

* Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.


Failure to follow the procedures exactly as written may result in serious injury or death.


1. Ignition OFF, disconnect the 42V harness connector X2 at the APM.
2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 3 ohms between the ground circuit terminal 1 X2 of the APM and ground.

• If greater than the specified range, test the APM ground circuits for an open/high resistance. If the circuits test normal, replace the APM.

3. Ignition OFF, connect a DMM between the 42V+ circuit terminal 2 X2 of the APM and ground.
4. Ignition ON, command the APM Intermediate Voltage Control ON with a scan tool. Test for 37.5-60 volts between the 42V+ circuit terminal 2 X2 terminal and ground. Command the APM Intermediate Voltage Control OFF after completing this test.

• If not within the specified range, replace the APM.

5. Ignition OFF, verify that the 42V harness connector X2 is connected under the PSCM.

• If the connector is not connected, connect the connector.

6. If all circuits test normal, replace the PSCM.

Low Voltage When Turning

1. Inspect the steering system for mechanical binding. The steering should have a heavy feel, if the power steering is disabled, but should not bind.

• If there is any mechanical binding in the steering system, refer to Steering Effort Hard in One or Both Directions (Standard) (Steering Effort Hard in One or Both Directions (Standard))Steering Effort Hard in One or Both Directions (HP2) ().

2. If all circuits test normal, replace the power steering motor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Power Steering Assist Motor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for APM or PSCM replacement, setup and programming

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