This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.
Ignition/Distributor Engine Speed Input Circuit Malfunction
Most DIY mechanics and professional automotive technicians see an OBDII P0320 code on their diagnostic tool when there is an issue with the ignition system or distributor engine speed input circuit. The onboard diagnostic computer gets a reading outside the manufacturer specified electrical range, and saves the code in the diagnostic computer. Next, the check engine light will turn on or the computer will display a message on the vehicle information display.
Like most trouble codes, there are a limited number of causes. Here is a brief list of the most common reasons a vehicle will code P0320
- Defective CKP sensor (Crankshaft Position Sensor).
- Issues with the CKP sensor or CMP (Camshaft Position) sensor circuits, such as broken, frayed or loose wires and connectors.
- Faulty CMP sensor.
- Damaged crankshaft or camshaft sensor tone wheel.
- An issue with the PCM (Power Control Module), such as software in need of an update.
Here are the typical symptoms of a P0320 OBDII trouble code:
- The check engine light switch is illuminated, or there is a check engine message on the vehicle information display.
- Your engine hard starts or refuses to start despite extended cranking.
- Your vehicle stalls or hesitates when accelerating.
- Your vehicle engine dies and refuses to restart.
Troubleshooting the electronic ignition and distributor system for any vehicle can be a daunting task. It’s even more challenging in newer vehicles with sophisticated electronic controls. Most drivers leave this type of task to their trusted auto shop technician or dealership mechanic.
However, if you feel confident in your DIY car repair skills, you can try tracking down the root cause of the trouble code and fixing it yourself. Here’s a brief overview of steps you can take to find the source of a P0320.
- Check the wiring and connectors going to and from your CKP, CMP and PCM. Replace or tighten any loose connectors, and repair and replace any loose or damaged wiring. Clear the codes and test again to see if the code is still saving. Most electrical trouble codes are triggered by faulty wiring or connectors, so start with the wiring and go from there.
- If you are still seeing a P0320, you will need to use a digital multimeter to test each sensor (CKP, CPM, and Ignition/Engine Distributor Speed Sensor). Each component should be sending and receiving the correct voltage and amperage. You can look up the manufacturer specifications online or in a maintenance manual for your specific vehicle. If one of the sensors is not reading correctly on the multimeter test, it will need to be replaced.
- Finally, if your vehicle is still coding P0320, you should take it to a professional to have a diagnostic run on your PCM. The OBDII diagnostic tools used for PCMs are expensive and sophisticated, and they require specialized skill and knowledge to operate and read.
Additionally, if the PCM does need to be replaced, it is a complex and expensive repair best left to professionals. Making a mistake during replacement can damage or destroy the PCM and/or any connected components. It truly is not a task for amateurs, especially when the work and part are not insured.
Many DIY auto repair technicians frequently replace the wrong sensor when correcting a P0320. Some rely on guesswork instead of testing with a multimeter, and that is the primary cause of replacing the wrong sensor. The most common mistake is to replace the crankshaft sensor when the actual issue is the ignition/distributor engine speed sensor.
The second most common mistake is to replace the crankshaft sensor instead of the camshaft sensor. Both sensors work together closely to accomplish a joint function, so it is important to replace the correct sensor the first time. Otherwise, you may end wasting money by replacing one unnecessarily and then having to replace the other anyway.
It’s also smart to keep in mind that a P0320 is an engine misfire code, and they usually don’t pop up by themselves. There are other misfire problems that can trigger a P0320 alongside other codes. You may need to troubleshoot the other code issues before the P0320 will go away.
Finally, always check the wiring before you start replacing expensive parts. DIY mechanics waste thousands of dollars every year, replacing parts unnecessarily when the cause of their trouble code was faulty wiring and connectors. Take the extra time to check the wiring first, and save yourself time and headaches.
How serious is this?
In the grand scheme of automotive problems, a P0320 is only moderately serious. If you pull the code and you aren’t experiencing any performance issues, the vehicle should remain drivable if unreliable.
That being said, don’t delay too long getting the problem diagnosed and repaired. Continuing to drive your vehicle with this problem only makes it worse, and it can potentially damage other engine components, too.
What repairs can fix the code?
Here are the most common repairs for correcting a P0320 trouble code:
- Diagnose/repair any low battery voltage issues.
- Replacing the crankshaft position sensor or any of its faulty wiring/connectors.
- Replacing a camshaft position sensor or any of its faulty wiring/connectors.
- Replacing an ignition/distributor engine speed sensor or any of its faulty wiring/connectors.
- Diagnose and repair any concurrent misfiring codes stored in the ECM (Electronic Control Module).
- Replace or update/reprogram the ECM.
Ultimately, seeing a P0320 code on the list of trouble codes in your OBDII scanner, take it to an auto repair shop as soon as possible. It will most likely remain driveable for a while, but delaying too long can turn a minor repair into a major one. Make an appointment as soon as you check your codes, and don’t let a small malfunctioning component cause extensive damage.