Circuit Description
This ignition system does not use a conventional camshaft position (CMP) sensor that detects valve train position. The ignition controls module (ICM) detects when #1 or #3 cylinder has fired on the cylinders compression stroke using sensing circuitry integrated within each coil. The sensing circuit detects the polarity and the strength of the secondary voltage output, the higher output is always at the event cylinder. The ignition control module (ICM) sends a CMP signal to the powertrain control module (PCM) based on the voltage difference between the event and waste cylinder firing energy. This system is called compression sense ignition. By monitoring the CMP and crankshaft position (CKP) signals, the PCM can accurately time the operation of the fuel injectors. If the PCM receives an intermittent CMP signal from the ICM, the CMP Resync Counter on the scan tool will increment. When the PCM cannot use the information from the CMP signal, a DTC will set. DTC P0341 sets when the PCM detects too many CMP Resyncs within a certain amount of time.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The PCM does not detect any change in the CMP sensor signal for 35 crankshaft revolutions, 70 combustion events, when manifold absolute pressure (MAP) is at 30 kPa or greater.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | If DTC P0336 is also set, diagnose that DTC first. An Intermittent crank signal will result in an interrupted cam signal and may set this DTC. |
| • | To locate an intermittent problem, use the scan tool to monitor CMP Active Counter while running the engine. The counter should continuously count up to 255, then reset to zero. The counter will stop counting if a fault occurs in the cam signal circuit. |
| If this DTC is determined to be intermittent, refer to Intermittent Conditions . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the ignition system is working correctly .
-
This step determines if the interconnect is bad or if a poor connection exists between the ICM and the Coil Cassette.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Does the scan tool indicate the CMP active counter is incrementing? | -- | Go to Step 3 | Go to Step 4 |
3 |
Does the DTC reset? | -- | Go to Step 4 | Go to Diagnostic Aids |
Is the duty cycle within the specified range? | 45-55 % | Go to Step 6 | Go to Step 5 | |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 12 | |
6 |
Is the voltage above the specified value? | 1 V | Go to Step 9 | Go to Step 7 |
7 |
Is the resistance within the specified range? | 0-5 ohms | Go to Step 8 | Go to Step 10 |
8 |
Is the resistance at the specified value? | OL | Go to Step 14 | Go to Step 11 |
9 | Test the CMP signal circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 |
10 | Test the CMP signal circuit for a open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 12 |
11 | Test the signal circuit of the CMP sensor for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 |
12 | Inspect for poor connections at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
13 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
14 | Inspect for poor connections at the PCM . Refer to Wiring Repairs in Wiring Systems Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 |
15 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
16 |
Does the DTC run and pass? | -- | Go to Step 17 | Go to Step 2 |
17 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
