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DTC P0812

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 P0812 00: Reverse Position Switch Circuit Malfunction

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Reverse Switch Signal

P0812 00

1

P0812 00

-

Ground

--

1

1

-

1. Reversing Lights Malfunction

Circuit/System Description

The reverse gear switch is a normally open switch that closes with the reverse gear engagement. When the switch is open the engine control module (ECM) should detect a high signal voltage input. When the switch is closed the ECM should detect a low signal voltage input.

Conditions for Running the DTC
    • No vehicle speed sensor faults exist.
    • Reverse switch is ON.

Conditions for Setting the DTC

The ECM detects circuit malfunction of the reverse input switch.

Action Taken When the DTC Sets

DTC P0812 00 is Type C DTC.

Conditions for Clearing the DTC

DTC P0812 00 is Type C DTC.

Reference Information

Schematic Reference

Manual Transmission Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission System Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Reverse Switch parameter. The reading should be Off and change to On when the transmission is shifted into reverse.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the B16 Reversing Light Switch.
  2. Ignition OFF, test for less than 5 Ω between the ground circuit terminal B and ground.
    3. ⇒If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Reverse Switch parameter is Off.
    4. ⇒If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
  4. Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool Reverse Switch parameter is On.
    5. ⇒If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
  5. If all circuits test normal, test or replace the B16 Reversing Light Switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Reverse Lamp Switch Installation
    • Control Module References for ECM replacement, setup and programming
   


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