For 1990-2009 cars

### Circuit Description

The camshaft position (CMP) sensor indicates the camshaft position so the powertrain control module (PCM) can determine which cylinder is misfiring when a misfire is present. With the engine running, the CMP activity counter will increment. Whenever the PCM receives an intermittent signal from the CMP, then the CMP resync counter will increment.

### Conditions for Running the DTC

The engine is running.

### Conditions for Setting the DTC

There is no change in the cam activity for 30 crankshaft revolutions.

### 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

• | Whenever the PCM sees less than 15 resyncs in 256 seconds, the counter resets to 0. When a poor connection is present, the cam sensor active counter stops incrementing, and the cam sensor resync counter starts to increment.

• | Inspect the wiring harness for damage. If the harness appears to be OK, observe the CMP resync counter on the scan tool while moving connectors and wiring harnesses related to the CMP sensor. If the CMP resync counter still does not count, then while still observing the scan tool, operate any non-engine related electrical components on the vehicle. A change in display will indicate the location of the malfunction.

• | A defective reluctor wheel or a cracked or damaged CMP sensor can result in an intermittent. Remove the camshaft sensor and inspect for any damage. With the CMP sensor removed you can also inspect the reluctor wheel through the hole. Check the porosity and condition of the wheel. The edges must be square, look for a nicked or damaged wheel.

If the condition is intermittent, refer to Intermittent Conditions .

### Test Description

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

1. This step determines if there is a problem with the signal circuit.

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 the scan tool.
2. Start and idle the engine.
3. Use a scan tool in order to monitor the CMP active counter.

Does the scan tool indicate the CMP active counter is incrementing?

--

Go to Step 3

Go to Step 4

3 |

1. Observe the Freeze Frame/Failure Records and 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 as possible to 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 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 the 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. Observe the CMP active counter 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 the CMP active counter 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 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 the PCM. 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 PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | --
14 | Inspect for poor connections at the CMP sensor. 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 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, review 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