For 1990-2009 cars

### Circuit Description

During cranking, the ignition control (IC) module monitors the 7X crankshaft position sensor signal. Once the IC module determines spark synchronization, 3X reference signals are sent to the powertrain control module (PCM). The PCM will command all 6 injectors on for 1 priming shot of fuel in all cylinders. After the priming, the injectors are left OFF for the next 6 fuel control reference signals, or 2 crankshaft revolutions. This process allows 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 24 X reference pulses and the number of 3 X 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 1-in-6 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, and the 3X reference pulses are being received.

### Conditions for Setting the DTC

The CMP sensor reference pulse is not detected during every engine cycle.

### 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

DTC P0341 can be caused by the secondary components leaking high voltage into the ignition module. Inspect for the following conditions:

• | An incorrect harness routing near the secondary ignition components

• | The ignition coil arcing to the wiring harness or to the IC module--Inspect the ignition coils for cracks, for carbon tracking, or for other signs of damage.

• | The secondary ignition wires arcing to the wiring harness

If the condition is intermittent, refer to Intermittent Conditions .

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. The cam signal on the scan tool should change each time the signal circuit is touched.

2. If the fuse is open in the jumper wire, there is a short to ground on the signal circuit.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Engine Controls Schematics
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls
2 |

1. Install a scan tool.
2. Start the engine.
3. Use a scan tool in order to monitor the CMP sensor input signal in the Engine Data List 2.

Does scan tool indicate the CMP sensor signal is present?

--

Go to Step 3

Go to Step 4

3 |

1. Observe the Freeze Frame/Failure Records data.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close the Freeze Frame/Failure Records data that you observe.

Does the DTC reset?

--

Go to Step 4

Go to Diagnostic Aids

4 |

1. Turn OFF the ignition.
2. Disconnect the CMP sensor connector.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage on the CMP 12-volt reference circuit using the DMM connected to battery ground.

Does the voltage measure near the specified value?

B+

Go to Step 6

Go to Step 5

5 |

1. Turn OFF the ignition.
2. Disconnect the PCM connector C2.
3. Test the 12-volt reference circuit of the CMP sensor for a short to ground or for an open. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 12

6 |

1. Connect a test lamp to battery positive voltage.
2. Touch CMP sensor low reference circuit.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 7

7 |

1. Turn OFF the ignition.
2. Disconnect the PCM connector C2.
3. Test the low reference circuit of the CMP sensor for an open. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 12

8 |

1. Start the engine.
2. Monitor cam signal on the scan tool.
3. Connect a 5-amp fused jumper wire to battery positive voltage and momentarily touch the signal circuit 5 times for a duration of 1 second each.

Does cam signal change EACH time the signal circuit is touched?

--

Go to Step 14

Go to Step 9

9 | Did the fuse in the jumper wire open? | -- | Go to Step 11 | Go to Step 10
10 | Test the signal circuit of the CMP sensor for a short to voltage or for an open. Refer to Circuit Testing and 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 Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 12
12 | Inspect for poor connections at PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13
13 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | --
14 | Inspect for poor connections at CMP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15
15 | Replace CMP sensor. Refer to Camshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 16 | --
16 |

1. Use the scan tool in order to clear the DTCs.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

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? | -- | Go to Diagnostic Trouble Code (DTC) List | System OK