GM Service Manual Online
For 1990-2009 cars only

DTC C0900 EBCM

Diagnostic Instructions

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

DTC Descriptor

DTC C0900 00: Device Voltage High - EBCM

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+

C0899 00

C0899 00

--

--

Ground

--

C0899 00

--

--

Typical Scan Tool Data

Battery Voltage Signal - EBCM

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Ignition ON, engine OFF.

Parameter Normal Value: 12.60 Volts

B+

0.00 Volts

0.00 Volts

12.60 Volts

Circuit/System Description

The electronic brake control module (EBCM) monitors the ignition voltage. If the voltage level is too high, damage may result in the system. When a high voltage condition is detected the EBCM turns OFF the system relay which removes battery voltage from the solenoid valves and pump motor.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The system voltage is greater than 16 volts for 100 msec.

Action Taken When the DTC Sets

    • The traction control system (TCS) and vehicle stability enhancement system (VSES) are disabled for the duration of the ignition cycle.
    • The ABS is disabled if ignition voltage exceeds 19.5 volts.
    • The stability system off and traction control off indicators turn ON.
    • The antilock brake system (ABS) indicator turns ON if voltage exceeds 19.5 volts.

Conditions for Clearing the DTC

    • The DTC will pass when the condition for the DTC is no longer present.
    • The EBCM automatically clears a history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

    • Overcharging with a battery charger or jump starting may set this DTC.
    • A high voltage DTC in multiple modules indicates a concern in the charging system.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Antilock Brake System Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

  1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 volts.
  2. If not within the specified range, refer to Charging System Test .
  3. Observe the scan tool EBCM Battery Voltage Signal parameter. The reading should be between 12.6 and 15.0 volts.
  4. If not within the specified range, replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup, and programming.

DTC C0900 PSCM

Diagnostic Instructions

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

DTC Descriptor

DTC C0900 00: Device Voltage High - PSCM

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+

C0899 00

C0899 00

--

--

Ground

--

C0899 00

--

--

Typical Scan Tool Data

Battery Voltage Signal - PSCM

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Ignition ON, Engine OFF.

Parameter Normal Value: 12.60 Volts

B+

0.00 Volts

0.00 Volts

12.60 Volts

Circuit/System Description

The power steering control module (PSCM) monitors the amount of battery voltage available to it. If the voltage is too high, then the PSCM sets DTC C0900 00 and disables itself in order to protect itself against high voltage damage.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

Power steering system voltage is greater than 16 volts for 1 second.

Action Taken When the DTC Sets

    • The PSCM is disabled.
    • No steering assist is provided.
    • The driver information center (DIC) displays the POWER STEERING message.

Conditions for Clearing the DTC

    • A current DTC will clear when the power steering system voltage returns to less than 16 volts.
    • A history DTC will clear after 100 consecutive ignition cycles from when power steering system voltage is less than 16 volts.

Diagnostic Aids

    • Overcharging with a battery charger or jump starting may set this DTC.
    • A high voltage DTC in multiple modules indicates a concern in the charging system.

Reference Information

Schematic Reference

Power Steering Schematics

Connector End View Reference

Power Steering Connector End Views

Description and Operation

Power Steering System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

  1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 volts.
  2. If not within the specified range, refer to Charging System Test .
  3. Observe the scan tool PSCM Battery Voltage Signal parameter. The reading should be between 12.6 and 15.0 volts.
  4. If not within the specified range, replace the PSCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PSCM replacement, setup, and programming.