Refer to
Ignition Control, Knock Sensors
.
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 Setting the DTC
| • | The engine is running (3X reference pulses are being received). |
| • | The ratio of 3X reference pulses to Cam pulses received by the PCM does not equal 6. |
| • | The ratio of 3X reference pulses to 18X reference pulses received by the PCM equals 6. |
| • | Above conditions for 290 occurrences. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the MIL during the second consecutive trip cycle in which the diagnostic test has been run and failed. |
| • | The PCM will initiate injector sequence without the camshaft position signal with a one in six chance that injector sequence is correct. |
| • | If equipped with traction control, the PCM will command the EBTCM via serial data (CKT 800) to set an ABS/TCS DTC, the EBTCM will 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 OFF the MIL 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 the scan tool. |
Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for the following conditions:
| • | 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 ICM or ICM wiring harness. Refer to Ignition Control Module Replacement . |
| • | Secondary ignition wire(s) arcing to wiring harness. Check secondary ignition wires for carbon tracking or other signs of damage. |
| • | 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 ICM and the CMP sensor. A change in voltage will indicate the location of the malfunction. |
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.
-
Ensures that the fault is present.
-
Determines whether the fault is being caused by a missing camshaft magnet or a faulty PCM. The voltage measured in this step should read around 4 volts, toggling to near 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 being replaced, the new PCM must be programmed.
Step | Action | Value(s) | 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? | -- | Refer to Diagnostic Aids | ||||||||
3 |
Does the Digital Multimeter display a voltage near the specified value? | 5V | ||||||||
4 |
Does the Digital Multimeter display voltage near the specified value? | 0V | ||||||||
5 | Does the voltage on the camshaft position input signal circuit measure greater than the specified value? | 5V | ||||||||
6 |
Was a problem found? | -- | ||||||||
7 |
Was a problem found? | -- | ||||||||
8 |
Does the voltage measure near the specified value? | B+ | ||||||||
9 | Measure voltage between the CMP sensor signal circuit and the sensor ground circuit at the camshaft position sensor harness connector. Does the voltage measure between the specified values? | 5-7V | ||||||||
10 |
Does the Digital Multimeter voltage display switch between 0 and 5 volts when the test light 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 . Is the action complete? | -- | -- | |||||||
19 | Replace the camshaft position sensor. Refer to Camshaft Position Sensor Replacement . Is the action complete? | -- | -- | |||||||
20 |
Was a problem found? | -- | ||||||||
Does voltage toggle between the specified values? | 4V / 0V | |||||||||
Replace the PCM. Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||||||||
23 | Replace faulty or missing camshaft position sensor magnet. Refer to 3800 Engine Unit Repair . Is the action complete? | -- | -- | |||||||
24 |
Does the scan tool indicate DTC P0341 failed this ignition? | -- | System OK |
