P1374
DTC P1374CIRCUIT DESCRIPTION
The powertrain control module (PCM) uses the 3X reference pulses from the ignition control module (ICM) to calculate engine RPM, and crankshaft position at engine speeds above 1,200 RPM. The 3X reference signal is produced by the ICM and passed to the PCM on the low-resolution engine speed signal circuit. The PCM constantly compares the number of 18X reference pulses to the number of 3X reference pulses and camshaft position signals being received. If this DTC sets, the engine will continue to start and run using the cam signal and 18X reference pulses. The PCM will use the medium-resolution engine speed signal circuit for fuel injection and ignition control. If the PCM detects an incorrect number of 3X pulses during two crankshaft revolutions, DTC P1374 sets.
CONDITIONS FOR RUNNING THE DTC
The engine is running for more than 3 seconds.
CONDITIONS FOR SETTING THE DTC
- The PCM detects an incorrect number of 3X reference pulses during two crankshaft revolutions.
- The above conditions are present for up to 30 seconds.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- 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.
- Clear the MIL and the DTC with a scan tool.
TEST
