Refer to
Cell 21: Ignition Controls
Circuit Description
During cranking, the IC Module monitors the 7X crankshaft position sensor signal. Once the IC Module 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 3X 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 Running the DTC
The engine is running (3X reference pulses are being received).
Conditions for Setting the DTC
CMP sensor reference pulse is not detected every engine cycle.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle 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 PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. |
| • | The PCM writes the conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has 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 IC 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 IC Module or IC Module 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. Refer to Intermittents and Poor Connections Diagnosis Repairing Connector Terminals and Connector Repairs . |
| • | Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, turn the ignition on and observe a voltmeter connected to the CAM signal circuit at the PCM harness connector while moving connectors and wiring harnesses related to the 24X Crankshaft Position Sensor and Camshaft Position Sensor. The Camshaft Position and 24X sensors share the same sensor feed from the PCM. A change in voltage will indicate the location of the fault. Refer to Wiring Repairs . |
| • | It may also be helpful to monitor the CAM SIGNAL PRESENT on the scan tool. |
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
The numbers below refer to the step numbers on the diagnostic table:
-
The 24X RPM on the scan tool should change each time the signal circuit is touched.
-
If the fuse blows in the jumper wire, there is a short to ground on the signal circuit.
-
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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain OBD System Check performed? | -- | ||
2 |
Does scan tool indicate DTC P0341 failed this ignition? | -- | Go To Diagnostic Aids | |
3 | Using the scan tool monitor Cam Signal. Is Cam Signal Present? | -- | Go To Diagnostic Aids | |
4 |
Does DMM display a voltage near the specified value? | B+ | ||
5 |
Was a problem found? | -- | ||
6 |
Does test lamp illuminate? | -- | ||
7 |
Was a problem found? | -- | ||
Does Cam Signal change EACH time the signal circuit is touched? | -- | |||
Did the fuse in the jumper wire blow? | -- | |||
10 | Check signal circuit for an open or a short to voltage, repair as necessary. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
11 | Check signal circuit for a short to ground, repair as necessary. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
12 | Check connections at PCM and replace terminals as necessary. Refer to Intermittents and Poor Connections Diagnosis , and Repairing Connector Terminals in Wiring Systems. Did any terminals require replacement? | -- | ||
13 |
Important: : Replacement PCM must be reprogrammed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
14 | Check connections at CMP sensor and replace terminals as necessary. Refer to Wiring Repairs in Wiring Systems. Did any terminals require replacement? | -- | ||
15 | Replace CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Is the action complete? | -- | -- | |
Does scan tool indicate DTC P0341 failed this ignition? | -- | System OK |
