P0512

DTC P0512

CIRCUIT DESCRIPTION
The starter switch signal is inputted to the engine control module (ECM) during the ignition switch "START" position. The ECM uses the starter switch input for fuel crank mode and starter cut relay control. If the ECM detects the starter switch signal is ON when the engine is running, this DTC will set.

Condition for Running the DTC
- The battery voltage is between 10-16 volts.
- The ignition switch is ON.
- The engine speed is higher than 1000 RPM.

Condition for Setting the DTC
- The ECM detects that the starter switch signal circuit is in the ON position (high voltage) for longer than 10 seconds.

Action Taken When the DTC Sets
- The ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive driving cycle when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Freeze Frame/Failure Records on the second consecutive driving cycle when the diagnostic runs and fails.

Condition for Clearing the MIL/DTC
- The ECM turns OFF the MIL after 3 consecutive driving cycles when the diagnostic runs and does not fail. (12,000 lbs GVW)
- The ECM turns OFF the MIL when the diagnostic runs and does not fail. (Except 12,000 lbs GVW)
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic after the ECM turns OFF the MIL.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
If the engine does not crank normally, refer to the Starting System section.

If an intermittent condition is suspected, the following may cause an intermittent:
- Faulty ignition switch
- Misrouted harness
- Rubbed through wire insulation

Check for the following conditions:
- Damaged harness: Inspect the wiring harness for damage. If the harness appears to be OK, observe the "Starter Relay Status" display on the scan tool with the engine running while moving connectors and wiring harness. A change in the display will indicate the location of the fault.

DTC P0512
Schematic Reference: Engine Controls Schematics & Starting and Charging Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

Step 4 - 9:

Step 10 - 11: