P0341

Circuit Description

During cranking, the Ignition Control Module (ICM) monitors the 7X crankshaft position sensor signal. Once the ICM determines spark synchronization, 3X reference signals are sent to the PCM. The PCM will command all six injectors ON for one priming shot of fuel in all cylinders. After the priming, the injectors are left OFF for the next six fuel control reference signals (two crankshaft revolutions). This allow each cylinder a chance to use the fuel from the priming shot. During this waiting period, a cam pulse will have been received by the PCM. The PCM uses the Cam signal pulses to initiate sequential fuel injection. The PCM constantly monitors the number of pulses on the Cam signal circuit and compares the number of Cam pulses to the number of 24X reference pulses and the number of 3 X reference pulses being received. If the PCM receives an incorrect number of pulses on the Cam reference circuit, DTC P0341 will set and the PCM will initiate injector sequence without the Cam signal with a one in six chance that injector sequence is correct. The engine will continue to start and run normally, although the misfire diagnostic will be affected if a misfiring condition occurs.

Conditions for Setting the DTC

- The engine is running (3X reference pulses are being received).
- CMP sensor reference pulse is not detected every engine cycle.

Action Taken When the DTC Sets

- The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic has been run and failed.
- If equipped with traction control, the PCM will command the Electronic Brake and Traction Control Module (EBTCM) via the serial data circuit to turn OFF traction control, and the EBTCM will illuminate the TRACTION OFF lamp.
- The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC

- The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
- The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
- The DTC can be cleared by using a scan tool.

Diagnostic Aids

DTC P0341 can be caused by secondary components leaking high voltage into the ignition module. Check for the following conditions:

- Incorrect harness routing near secondary ignition component.
- Ignition coil arcing to wiring harness or Ignition Control Module (check ignition coils for cracks, carbon tracking, or other signs of damage).
- Secondary ignition wire(s) arcing to wiring harness.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for:

- Faulty Ignition Coil. Inspect the ignition coils for cracks, carbon tracking, or other signs that indicate that the coil secondary circuit is arcing to the ICM or ICM wiring harness.
- Poor connection. Inspect the PCM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Inspect the wiring harness for damage. If the harness appears to be OK, observe the Cam signal parameter on the scan tool while moving connectors and harnesses related to the sensor. A change in the display may indicate the location of the fault.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table:

8. The 24X RPM on the scan tool should change each time the signal circuit is touched.
9. If the fuse blows in the jumper wire, there is a short to ground on the signal circuit.
16. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.