For 1990-2009 cars
Engine Controls Components
Cell 21: CMP Sensor and CKP Sensor
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The crankshaft position (CKP) sensor is a magnetic generator type sensor, producing an alternating current signal. The CKP sensor sends the AC signal to the powertrain control module (PCM) in order to indicate crankshaft RPM and position. The CKP sensor reference signal is used by the PCM to calculate fuel injector pulse, establish top dead center for ignition timing, and determine the start of ignition coil and fuel injector sequencing. There will be no spark or fuel delivery if there is no CKP sensor signal.

### Conditions for Setting the DTC

• | Engine is cranking.

• | No signal from the CKP sensor for 2 seconds.

### Action Taken When the DTC Sets

• | The PCM illuminates the malfunction indicator lamp (MIL).

• | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

### Conditions for Clearing the MIL/DTC

• | The MIL turns OFF after three consecutively passing trips without a fault present.

• | A History DTC clears after 40 consecutive warm-up cycles without a fault.

• | Use the scan tool Clear DTC Information function or disconnect the PCM battery feed in order to clear the DTC.

### Diagnostic Aids

Check for any of the following conditions:

• | The CKP sensor can be checked off the vehicle by connecting a DMM to the sensor electrical terminals. Tap gently on the pick-up end (magnetic end) of the CKP sensor with the metal (iron) shaft of a screw driver while observing the ohms scale on the DMM. The DMM should switch from 360-460 ohms to infinity and back to 360-460 ohms.

• | The CKP sensor performance may be affected by temperature. Check the sensor's operation and internal resistance at various temperatures.

• | Check the wiring harness boot covering the CKP sensor electrical connectors for water intrusion. Water entry into the CKP sensor electrical connections may cause an intermittent loss of the CKP sensor signal.

• | Check the CKP sensor signal rotor for foreign material or damaged teeth.

• | A DTC P0335 that sets while driving and checks OK may be caused by inadequate CKP sensor circuit shielding. Check that the CKP sensor circuit is properly shielded and that the drain wire has a good ground.

• | The PCM relies on the CKP sensor for engine reference. Without continuous accurate reference signals, there is no reliable spark or fuel injector pulse. A CKP sensor Ignition Reference Low circuit that is shorted to ground will cause a faulty engine reference signal to be sent to the PCM, but will not set a CKP sensor DTC P0335.

An intermittent malfunction may be caused by a fault in the CKP sensor electrical circuit. Inspect the wiring harness and components for any of the following conditions:

• | Backed out terminals.

• | Improper mating of terminals.

• | Broken electrical connector locks.

• | Improperly formed or damaged terminals.

• | Faulty terminal to wire connections.

• | Physical damage to the wiring harness.

• | A broken wire inside the insulation.

If a DTC P0335 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. This step determines if fault is present.

3. This step checks the CKP sensor resistance. If the CKP sensor resistance is within the specified value, measure the resistance from each terminal of the CKP sensor to ground. Replace the CKP sensor if the sensor resistance is less than 1M ohm.

4. This step checks for an open or short in the CKP sensor's high and low reference circuits between the PCM and the CKP sensor.

5. This step checks for a faulty signal rotor. Visually inspect the teeth of the signal rotor through the CKP sensor aperture for damage, foreign material, and mis-alignment.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Turn ON the ignition, leaving the engine OFF.
2. Perform the scan tool Clear DTC Information function.
3. Operate the vehicle within the Freeze Frame conditions as specified.

Is a DTC P0335 set?

--

Go to Step 3

Go to Diagnostic Aids

3 |

1. Turn OFF the ignition.
2. Disconnect the CKP sensor electrical connector.
3. Measure the resistance of the CKP sensor with a DMM.

Is the resistance within the specified value?

360 to 460 ohms at 20°C (68°F)

Go to Step 4

Go to Step 8

4 |

1. Disconnect the PCM electrical connectors.
2. Check the CKP sensor high and low signal circuits for an open or a short.
3. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 10

Go to Step 5

5 |

1. Check for faulty electrical connections at the PCM and at the CKP sensor.
2. Repair as necessary.

Was a repair necessary?

--

Go to Step 10

Go to Step 6

6 |

1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
2. Visually inspect the CKP sensor for the following conditions:

• | Physical damage

• | Foreign material on the sensor (magnet) surface

• | Water or corrosion at the electrical terminals

3. Repair as necessary.

Was a repair necessary?

--

Go to Step 10

Go to Step 7

7 |

1. Visually inspect the signal rotor on the crankshaft timing belt pulley for the following conditions:

• | Damaged teeth

• | Foreign material

• | Correct installation

2. Repair as necessary.

Was a repair necessary?

--

Go to Step 10

Go to Step 9

8 | Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement . Is the action complete? | -- | Go to Step 10 | --
9 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 10 | --
10 |

1. Perform the scan tool Clear DTC Information function and road test the vehicle within the Freeze Frame conditions that set the DTC.
2. Review the scan tool data and check for DTCs. The repair is complete if no DTCs are stored.

Are any DTCs displayed on the scan tool?

--

Go to the Applicable DTC Table

System OK