MISFIRE P2308

[nickscarcare]

So I will see if we get any chimes on this one. I have a 20120 Dodge journey, 3D4PG5FV1AT257329 with 55,000 miles. The cust brought us the vehicle had codes P0206, P0205, P0204, P0201, P0660 after she manually washed it, ran rough, towed it here, runs good, cleared codes test drive and no issues. She did not wash under hood. Day later light comes back on same injector codes but no P0660 this time. We look at it clear codes, test drive runs good. A week or so goes by she tows it in with a dead misfire, code P3208 ionization code. We check everything, fuel looks good, spark is good, compression is good, running compression test is good. She wants a tune up anyways so we put in OE plugs, and coil in cylinder 3, and she wanted an injector, so that was done. Start it up seems to run good for first 2 seconds the kicks in the P2308. Nothing we do can get rid of this code. Even tried running it on propane and runs good for first 2 seconds then code kicks in, when it does it kills the injector and coil. Any thoughts on this one??? We are thinking possibly PCM which 2 have been put in already for other issues a year or so ago.

[ricmorin]

I assume the injector and the coil were OEM? I would swap one of the known good coils and see if the issue moves. If it doesn't, Id be carefully checking the wiring that controls the coil all the way to the PCM.

[nickscarcare]

Yes all OEM parts, does not matter if it is switched to another cylinder. We think we have a bad driver in the pcm.

[ricmorin]

Very possible. If wiring load tests ok my next step is scope that pattern next to a good cylinder pattern. Should see the difference.

[nickscarcare]

So here is the update, yes we scoped and the code sets so fast was hard to get a good signal, we actually put a custom tune into it and blocked out those codes and vehicle runs great, waveform looks good. Ordered a reman pcm, installed and not p2306 i believe it was for cylinder 1, got another pcm in and this one works great. Powers and grounds all load test great. This is the 5th pcm in it 2 were for a transmission issue, one failed in 6 months, this vehicle has had lots of issues for only 55,000 miles

[Daniel Kreider]

Just a thought ... you may want to check your alternator output waveform. Sometimes imbalance in the output voltage can cause strange symptoms such as ECM failures etc.