C0895 12 Chevrolet Tahoe III

Intermediate voltage is less than 26 volts.

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC

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

Diagnostic Aids

1. 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.
2. DTC C0895 may set if the engine stalls. Diagnose any engine stall DTCs in the ECM before diagnosing DTC C0895.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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

Connector End View Reference

Component Connector End Views

Description and Operation

1. «Power Steering System Description and Operation (Hydraulic Power Steering)»(ref-364521-S19772809882010063000000) or «Power Steering System Description and Operation (EPS)»(ref-364521-S40472930802010063000000)
2. «Charging System Description and Operation»(ref-364514-S40689560162010063000000)

Electrical Information Reference

1. «Circuit Testing»(ref-364488-S04114729552010063000000)
2. «Connector Repairs»(ref-364488-S23771656832010063000000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit. See Special Tools .