Refer to Engine Control Schematics
Circuit Description
The status of the lift pump is monitored by the PCM. This signal is
also used to store a DTC if the fuel pump relay is defective or fuel pump
voltage is lost while the engine is running. There should be about
12 volts on circuit 120 during glow plug cycle. The PCM
performs this DTC diagnostic continuously.
Conditions for Running the DTC
| • | The ignition switch is in the ON position. |
| • | The PCM has commanded the lift pump Off. |
Conditions for Setting DTC
| • | The lift pump signal voltage is less than 4 volts. |
| • | All diagnostic conditions met for 2 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the
second consecutive drive trip that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic
fails. The first time the diagnostic fails, the Failure Records will store
this information. If the diagnostic reports a failure on the second
consecutive drive trip, the Freeze Frame records the operating
conditions at the time of failure and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive trips without
a fault condition. |
| • | A History DTC will clear after forty consecutive warm-up cycles,
if this or any other emission related diagnostic does not report any failures. |
Diagnostic Aids
Important: Remove any debris from the PCM module connector surfaces before servicing
the PCM module. Inspect the PCM module connector gaskets when diagnosing/replacing
the moduel. Ensure that the gaskets are installed correctly. The gaskets
prevent contaminate intrusion into the PCM module.
This DTC will not check the fuel pump operation.
