The Chevy Express utilizes a crankshaft position sensor (CKP) in order to regulate the engine timing. This sensor uses a reluctor to gauge the position of the crank. When the Express’s ECM determines that the signal coming from this sensor is out of range, it’ll throw the P0336 trouble code. P0336 is most commonly caused by a bad crank sensor, reluctor ring issue, or wiring problems.
P0336 is most commonly caused by a bad crank sensor, reluctor ring issue, or wiring problems.
P0336 Symptoms: Chevy Express
Depending on the model year and engine of any vehicle the job of the crankshaft sensor is going to change. It’s either going to provide info to the ECM to keep the vehicle from misfiring. Or, it’ll provide necessary data to keep the engine timing in order.
Depending on whether or not the engine timing is dependent on the crank sensor is going to determine whether the symptoms of P0336 are going to be:
- Vehicle won’t start at all (timing dependent)
- Rough running motor
- Random Misfire (you may see P0300)
Often, if the crankshaft sensor or wiring itself is bad, there probably won’t be any RPM reading from the tachometer.
P0336 Causes: Chevy Express
Most of the time, the crankshaft sensor is going to be the cause of P0336, or the wiring will be at fault. There are other causes as well.
Here are the most common causes of P0336:
1. Bad Crank Sensor
The crankshaft sensor is often the reason that P0336 is thrown. They aren’t very expensive, but they can be difficult to get to in order to service them. If you think you’re up to the challenge (and know how to use a voltmeter) this guide from doityourself.com will show you exactly how to test the sensor.
2. Reluctor Ring
The crank sensor operates by scanning a “reluctor wheel”. This wheel can become damaged over time and will no longer give a proper reading to the ECM.
One of the most common symptoms of a bad reluctor ring is going to be a rattling sound. If the engine still runs, you will hear it. This means that it has been damaged, and no longer seated properly.
If you don’t hear a rattle, the ring could have broken or missing teeth. This will cause your Express to not get a good reading from the crank sensor.
3. Wiring Issues
Due to the location of the crankshaft position sensor, it is prone to damage. Start by inspecting the wiring harness between the firewall and crank sensor for any obvious damage. After that it would be prudent to look at the wiring harness plug at the sensor itself.
This YouTube video shows exactly how to test the wiring integrity, it’s for P0335, and is totally applicable for P0336.
4. Less Likely Reasons
Most of the time, the reasons outlined above are going to be the problem. But, not always. Here are some issues that are (not quite as) known to cause P0336 in the Express:
Timing Belt/Chain– It is possible that a vehicle that has jumped timing is throwing the code. Here’s more on diagnosing a bad timing chain from this site.
PCM/ECM– When the vehicle’s ECM goes bad, it can throw false trouble codes. This is definitely not the place to start, but is worth looking at if nothing else seems to be wrong. Symptoms of a bad ECM (Autoblog).
Conclusion: P0336 Chevy Express
Good luck determining what is causing P0336 in your Express. If you feel like there is anything you would like to add, please leave a comment below.