Refer to
IC Module, CMP and CKP Sensors
in Engine Controls Schematics.
Circuit Description
The camshaft position PCM input is produced by the ignition control module or ICM. 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 will illuminate the MIL during the second consecutive trip cycle in which the diagnostic test runs and fails. |
| • | 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 electronic brake and traction control module (EBTCM) via Serial Data to set an antilock brake system (ABS) and / ora traction control system (TCS) DTC. Then, the EBTCM will turn OFF traction control, and the TRACTION OFF lamp will illuminate. |
| • | The PCM will store conditions that 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 runs and passes. |
| • | 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 Clear Information function or by disconnecting the PCM battery feed. |
Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Inspect the following components and check for the following conditions:
| • | A poor connection--Inspect the PCM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Use a corresponding mating terminal to check for proper terminal tension. |
| • | A damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, and turn on the ignition. Observe a DMM connected to the 18X reference circuit at the PCM harness connector while moving the connectors and the wiring harnesses related to the ICM. A change in voltage will indicate the location of the malfunction. |
| • | A misrouted wiring harness--Inspect the ICM harness to ensure that it is not routed near secondary ignition components. |
| • | 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 ICM or ICM wiring harness. Refer to Ignition Coil Replacement . |
| • | Secondary ignition wires arcing to the wiring harness--Check secondary ignition wires for carbon tracking or other signs of damage. |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. 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 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, go 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 |
Does the J 39200 DMM display a voltage near the specified value? | 5 V | ||||||||
4 |
Does the J 39200 DMM display voltage near the specified value? | 0 V | ||||||||
5 | Does the voltage on the camshaft position input signal circuit measure more than the specified value? | 5 V | ||||||||
6 |
Was a problem found? | -- | ||||||||
7 |
Was a problem found? | -- | ||||||||
8 |
Does the voltage measure near 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. Does the voltage measure between the specified values? | 5-7 V | ||||||||
10 |
Does the J 39200 DMM voltage display switch between 0 and 5 volts when the J 35616-200 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 . Is the action complete? | -- | -- | |||||||
19 | Replace the camshaft position sensor. Refer to Crankshaft Position Sensor Replacement . Is the action complete? | -- | -- | |||||||
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. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM.Is the action complete? | -- | -- | ||||||||
23 | Replace malfunctioning or missing camshaft position sensor magnet. Refer to Camshaft Position Sensor Replacement . Is the action complete? | -- | -- | |||||||
24 |
Does the scan tool indicate DTC P0341 failed this ignition? | -- | System OK |
