What does this error code mean?
The diagnostic trouble code (DTC) in question is a generic powertrain code. It is considered generic because it applies to most vehicle makes and models (manufactured since 1996), although repair steps may vary slightly by manufacturer.
The crankshaft position sensor (CKP) is typically a two-wire device: one signal and one ground. This sensor usually consists of a permanent magnet mounted in front of a reluctor wheel (or toothed wheel), attached to the crankshaft. As this wheel passes in front of the sensor, an alternating (A/C) signal is generated. This signal varies with engine speed and is interpreted by the PCM (powertrain control module) to calculate engine RPM.
Some CKP sensors use Hall effect technology instead of a permanent magnet. These three-wire sensors operate using a power supply, ground, and signal. They also use a reluctor wheel, but their operation relies on a voltage change sent to the PCM, providing accurate engine speed data. This article focuses on permanent magnet sensors, which are more common and simpler in design.
CKP Sensor Operation
The crankshaft’s reluctor wheel has a specific number of teeth. Through this unique pattern, the PCM can not only identify the crankshaft’s position but also detect misfires by measuring variations in the CKP signal. Combined with the camshaft position sensor (CMP), the PCM can synchronize ignition and fuel injection. If the PCM detects a loss of signal, even momentarily, it may generate the error code P0336.
Error Codes Associated with the CKP Sensor:
- P0335: Crankshaft Position Sensor A Circuit Malfunction.
- P0337: Crankshaft Position Sensor A Circuit Low Input.
- P0338: Crankshaft Position Sensor A Circuit High Input.
- P0339: Crankshaft Position Sensor A Circuit Intermittent.
Symptoms of Code P0336:
- Intermittent stalling or failure to start.
- Difficulty starting the engine.
- Illumination of the Malfunction Indicator Lamp (MIL).
- Intermittent misfires.
Possible Causes:
- Crankshaft sensor failure.
- Damaged reluctor ring (broken teeth or debris).
- Mispositioned or loose reluctor ring.
- Damaged wiring harness causing a short circuit.
- Open or faulty CKP wiring.
Possible Solutions:
Issues related to the CKP sensor can be intermittent, making diagnosis sometimes complex. Here are some steps to identify and resolve the problem:
- Initial Check:
If the engine stalls or fails to start, observe engine speed data using an oscilloscope or code reader. The absence of RPM reading indicates a potential issue with the CKP sensor. - Visual Inspection:
Inspect the CKP sensor harness for cracks or damage. Ensure the cables are not near spark plug high-tension wires. Check connectors for loose or damaged connections. - Resistance Test:
Remove the CKP sensor and measure its resistance according to the manufacturer’s specifications. If the resistance is out of range, replace the sensor. - Reluctor Ring Examination:
Check the reluctor wheel for damage, broken teeth, or debris. Ensure the ring is properly secured to the crankshaft. - Repair or Replacement:
If the ring is damaged or mispositioned, repair or replace it. Note that some reluctor rings are difficult to access, especially those located in the bell housing or behind the engine.
Note:
If, after checking the wiring and replacing the CKP sensor, the problem persists, it may be necessary to consult a professional to inspect hard-to-reach components.