Questions and Answers

Stratus DTC Q. Hi, my name is Sergio Kigel. I'm writing you from Montevideo, Uruguay. I'm a technician and I'm a having a problem with a memory code from an OBD II. The vehicle data is: Chrysler model Stratus LX 2.5 V-6 VIN number: IC3EJ56HOVN517133.

It has a Memory Code P0302 that's related to the spark's failure of the cylinder number 2. I already changed the candle wire. My question is: Can somebody tell me if it's common that the computer indicates this as a failure or it might be a problem that comes from another place? (Or the module signal, or the turn on role)

My doubt is that the problem persists in the memory code, that means that in a certain moment it does a failure and later stays in a normal condition, but the light of the board stays on. What I want to know is (and you might know by your experience with this kind of vehicles) if the failure detected is caused by another reason that I might ignore?

I know that I have to check the turn on role and the signal of the module injection, but in my opinion that's not the problem. That's why I'm asking for some help.

I need also some Manual Code of verification step by step. Thank you very much.

Best Regards,
Sergio

A. Let me give you the basic information on this code and you'll be better able to understand it.

Name of code:
Cylinder #1, #2, #3, #4, #5, #6 misfire.

When monitored:
With the engine running, after successfully performing a crank sensor learn.

Set condition:
When more than a 2% misfire rate is measured during two trips, or with a 10% to 30% misfire rate during one trip.

Theory of operation:
Misfire is detected by the crankshaft speed fluctuation (CSF) method. This method compares the engine speed difference between the cylinders in firing order. The speed is detected by the crankshaft position sensor. An RPM value is set for each cylinder for comparison. When an RPM difference of more than 10 RPM between the cylinders, a misfire count of 1 is recorded. The RPM can vary 1 to 10 RPM depending on engine load. Two types of misfires are detected, a two-trip misfire which is about 2% and results in an emission increase, or a one-trip misfire which is about 10% - 30% and will damage the catalytic converter.

Possible causes:

• Secondary Ignition wires.
• Faulty connections.
• Spark plug, wire or connector.
• mechanical engine problem.
• Injectors.
• PCM.
• Ignition coil circuit.

This is one of the more common DTCs since a misfire is a common problem. I think the information I gave you here will help you track it down. Basically anything that will cause a miss is suspect. I checked the Chrysler TSBs and there is no mention of this being a concern so I'm pretty sure that the problem is in one of the systems I mentioned above.

If it is an intermittent misfire, it will be tough to track down without the use of test parts. Wiring and connectors can be checked first so that will be eliminated should the code persist.

I hope this helps.

Additional Information provided courtesy of ALLDATA