P0687

DTC P0687

CIRCUIT DESCRIPTION
The engine control module (ECM) main relay is energized when the ECM receives an ignition switch ON signal. If the ECM detects the ECM main relay has been ON since the ignition switch was turned OFF, this DTC will set.

Condition for Running the DTC
- The ignition switch is OFF.
- The engine is stopped.

Condition for Setting the DTC
- The ECM detects that the ECM main relay has been ON (high voltage) for longer than 5 seconds since the ignition switch was turned OFF.

Action Taken When the DTC Sets
- The ECM will not illuminate the malfunction indicator lamp (MIL) 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 Failure Records.

Condition for Clearing the DTC
- 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 non-emission related diagnostic.
- Clear the DTC with a scan tool.

Diagnostic Aids
If an intermittent condition is suspected, the following may cause an intermittent:
- Faulty or sticking ECM main relay
- Misrouted harness
- Rubbed through wire insulation
- Damaged harness: Inspect the wiring harness for damage. If the harness appears to be OK, observe the "DTC P0687" display on the scan tool while moving connectors and wiring harness. A change in the display will indicate the location of the fault.

Test Description
The numbers below refers to the step number on the diagnostic table.
2. If this DTC is present condition, scan tool can communicate to the ECM with the ignition OFF.

DTC P0687
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

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