GM Service Manual Online
For 1990-2009 cars only

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 P0801: Reverse Lockout Solenoid Control Circuit

Diagnostic Fault Information

Clutch Safety Switch

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+ Circuit to Reverse Lockout Solenoid

P0801

P0801

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--

Reverse Lockout Solenoid Control Circuit

P0801

P0801

P0801

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Typical Scan Tool Data

Reverse Inhibit Solenoid

Display Parameters

Normal Range

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine Running.

Parameter Normal Range: ON or OFF.

Reverse Inhibit Solenoid Command

ON/OFF

OFF

OFF

OFF

Circuit/System Description

Battery Voltage (B+) is supplied directly to the reverse lockout solenoid. The engine control module (ECM) controls the reverse lockout solenoid by grounding the control circuit via an internal switch called a low side driver. The low side driver has a fault line which monitors the control circuit. When the ECM commands the reverse lockout solenoid ON, the voltage should be low, near zero volts. When the ECM commands the reverse lockout solenoid OFF, the voltage should be high, near battery voltage.

Conditions for Running the DTC

    • The engine is running.
    • The vehicle speed is less than 3 km/h (2 mph).

Conditions for Setting the DTC

    • The ECM detects that the commanded state of the driver and the actual state of the control circuit does not match.
    • The condition exists for 2 seconds.

Action Taken When the DTC Sets

P0801 is a Type C DTC.

Conditions for Clearing the DTC

P0801 is a Type C DTC.

Diagnostic Aids

    • The battery must be fully charged and pass a battery test. Refer to Battery Inspection/Test.
    • The reverse lockout solenoid is referred to as the reverse inhibit solenoid on the scan tool.

Reference Information

Schematic Reference

Manual Transmission Schematics

Connector End View Reference

Manual Transmission Connector End Views

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 Output Controls

Scan Tool Data Definitions

Circuit/System Verification

  1. Engine running, the reverse lockout solenoid parameter should display OFF.
  2. Road test the vehicle at 16 km/h (10 mph). The reverse lockout solenoid parameter should display ON.
  3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Circuit/System Testing

  1. Ignition OFF, disconnect the reverse lockout solenoid harness connector.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal B and ground.
  3. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the circuit protection fuse is open, then replace the reverse lockout solenoid.
  4. Verify that a test lamp does not illuminate between the B+ circuit terminal B and the control circuit terminal A.
  5. If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  6. Connect a test lamp between terminal A and terminal B on the reverse lockout solenoid harness connector.
  7. Command the reverse lockout solenoid ON with a scan tool. The test lamp should illuminate.
  8. If the test lamp does not illuminate, test the reverse lockout solenoid control circuit for an open/high resistance. If the circuit tests normal replace the ECM.
  9. If all circuits test normal, replace the reverse lockout solenoid.

Repair Verification

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Reverse Lockout Solenoid Replacement
    •  Engine Control Module Replacement
    •  Engine Control Module Programming and Setup