Refer to
Ignition Control Inputs
in Engine Controls Schematics.
Circuit Description
The camshaft position PCM input is produced by the ignition control module. The ICM produces the camshaft position PCM input by filtering the camshaft position (CMP) sensor pulses when the engine is running and CKP sync pulses are also being received. The PCM uses the camshaft position PCM input pulses to initiate sequential fuel injection and to determine crankshaft position for the misfire diagnostic. The PCM constantly monitors the number of pulses on the camshaft position PCM input circuit and compares the number of camshaft position PCM input pulses to the number of 18X reference pulses and the number of 3X reference pulses being received. If the PCM receives an incorrect number of pulses on the camshaft position PCM input circuit, DTC P0341 will set and the PCM will initiate injector sequence without the camshaft position PCM input 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 disabled.
Conditions for Running the DTC
The engine is running (3X reference pulses are being received).
Conditions for Setting the DTC
| • | The ratio of 3X reference pulses to CAM pulses received by the PCM does not equal 6 to 1. |
| • | The ratio of 3X reference pulses to 18X reference pulses received by the PCM equals 6 to 1. |
| • | The conditions are present for 290 of 300 test samples. |
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
An intermittent may be caused by a faulty connection, rubbed through wire insulation, or a wire broken inside the insulation. Check for the following conditions:
| • | A malfunctioning ignition coil--Remove the ignition coils and inspect the ignition control module and coils for cracks, carbon tracking, or other signs that indicate that the coil secondary circuit is arcing to the ignition control module (ICM) or the ICM wiring harness. Refer to Ignition Coil Replacement . |
| • | Secondary ignition wires arcing to the wiring harness--Check the secondary ignition wires for carbon tracking or other signs of damage. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, turn the ignition on and observe a DMM connected to the camshaft position input signal circuit at the PCM harness connector while moving connectors and wiring harnesses related to the ICM and the camshaft position (CMP) sensor. A change in voltage will indicate the location of the malfunction. |
Reviewing the Failure 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.
-
Ensures that the malfunction is present.
-
Determines whether the malfunction is being caused by a missing camshaft magnet or a malfunctioning PCM. The voltage measured in this step should read approximately 4 volts, toggling to approximately 0 volts when the CMP sensor interfaces with the camshaft magnet.
-
This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read-only memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 |
Important:: If the engine cranks but will not run, refer to Engine Cranks but Does Not Run . Was the Powertrain On Board Diagnostic (OBD) System Check performed? | -- | ||||||||
Does the scan tool indicate DTC P0341 failed this ignition? | -- | Go to Diagnostic Aids | ||||||||
3 |
Important: If the DMM indicates 0 volts, bump over the engine to ensure the cam sensor magnet is not located under the cam sensor at the time of this test. Does the voltage approximately equal the specified value? | 5 V | ||||||||
4 |
Important: The magnet used must have sufficient power and the correct polarity. If the voltage remains at 5 volts, retest using the opposite end of the magnet. Does the voltage approximately equal the specified value? | 0 V | ||||||||
5 | Is the voltage on the camshaft position input signal circuit more than the specified value? | 5 V | ||||||||
6 |
Was a problem found? | -- | ||||||||
7 |
Was a problem found? | -- | ||||||||
8 |
Does the voltage approximately equal the specified value? | B+ | ||||||||
9 | Measure the voltage between the CMP sensor signal circuit and the sensor ground circuit at the camshaft position sensor harness connector. Is the voltage within the specified range? | 5-7 V | ||||||||
10 |
Does the DMM voltage display switch between 0 and 5 volts when the test lamp is repeatedly touched to the CMP sensor signal circuit? | -- | ||||||||
11 |
Was a problem found? | -- | ||||||||
12 |
Was a problem found? | -- | ||||||||
13 |
Was a problem found? | -- | ||||||||
14 |
Was a problem found? | -- | ||||||||
15 |
Was a problem found? | -- | ||||||||
16 |
Was a problem found? | -- | ||||||||
17 |
Was a problem found? | -- | ||||||||
18 | Replace the ignition control module. Refer to Ignition Control Module Replacement . Did you complete the repair? | -- | -- | |||||||
19 | Replace the camshaft position sensor. Refer to Camshaft Position Sensor Replacement . Did you complete the repair? | -- | -- | |||||||
20 |
Was a problem found? | -- | ||||||||
Important: The magnet on the cam gear must pass the sensor in order for the test to be valid. Does voltage toggle between the specified values? | 4 V 0 V | |||||||||
|
Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the repair? | -- | -- | ||||||||
23 | Replace the malfunctioning or missing camshaft position sensor magnet. Did you complete the repair? | -- | -- | |||||||
24 |
Does the scan tool indicate DTC P0341 failed this ignition? | -- | System OK |
