A little background: I got codes P0306 and P0206 on my 2003 Dodge Grand Caravan and the engine was misfiring on cylinder 6. It turns out the fuel-rail wiring harness was fried by the exhaust manifold; all of the wire casings melted off on one end of the harness and caused some major problems. (I gather it's a relatively common problem; read more here http://forum.chryslerminivan.net/sho...wn-and-Country ).

I replaced the fried #6 injector and the bad wiring harness (adding a hefty amount of additional heat shielding material), but it's still misfiring on #6. I was told by another Dodge tech on the forum that there's a good chance that the bad wiring also broke one (or more) of the injector drivers in the PCM. I pulled codes again and I'm getting "P0206 Injector Circuit Open."

I'm not sure what to do from here. Are there more diagnosis steps I should take, or do I just need to suck it up and buy a new PCM? Thanks for helping.

 

PCM? Not yet. First verify you're not getting a driver pulse (ground turning on and off) to the injector from the PCM. Connect a noid light at the injector connector and start the engine. If it blinks all is good and you have another bad injector. If it doesn't blink either the wire from the PCM to injector #6 is open or the PCM driver is toast.

http://www.obd-codes.com/p0206

Example Any parts store should have them. If you get one make sure it's made for the van.

 

Thanks for your help.

I replaced the injector at the same time I replaced the wiring, so the new injector was never subjected to the shorts in the bad wiring harness. Since I already replaced the injector and wiring, the next thing on the list was PCM (unless the new injector is already bad). Given that I already replaced the #6 injector, do you still think it's still necessary to do the noid light test?

I have to take off the plenum to get to any of the injectors, so hopefully the wire is long enough that I can stick it out to the side after I put the plenum back on to start the engine.

Thanks again!

 

Odds are on your side meaning you're ready for a PCM. The noid light test is what you should have done first but just like all of us, you live and learn. It would reveal the smoking gun. It would eliminate any doubts before you open your wallet.

I'm thinking you can remove the injector connector without pulling the plenum. Maybe not. You're about to remove the PCM anyway right? If you like, instead of checking with a noid light you could go to the PCM connectors and using a multimeter, check resistance through the injector and wire from there. Any resistance indicates the injector coil is good and the wire from the PCM to the injector at least has some continuity. Up to you.

Can you give us more details on how you insulated the new harness? If you've got the time pictures would speak a thousand words. This is a common problem on 4th generation vans. You may help many who come across this.

BTW - Dealership will charge you somewhere around $500+ for a PCM. They can be had for far less on the internet. They come reprogrammed and ready for installation. Even Autozone and other parts stores sell them for less.

 

I apologize that I took so long to reply to your post; I got working on other things and forgot to post a response. I'm happy to provide more details on how I insulated the wiring.

I used a product called "Thermo-Shield" by a company called "Thermo-Tec." It's composite tape made of fiberglass and aluminum that protects from radiant heat up to 2000 F...really great stuff. I just taped up the areas that had been damaged on the old harness (plus a little extra for good measure). It's about $20 for a 15 ft roll, so it's a bit expensive, but it's much better than other cheaper tapes and is a lot less expensive than a new wiring harness! It only took 2 or 3 feet of tape to cover what I needed.

Here is a photo of the fix: http://i49.tinypic.com/15qw0n8.jpg
Here is a link to the product: http://www.thermotec.com/products/14...mo-shield.html (they make some other great heat shielding products too)

Regarding the fix, I ended up replacing the PCM and it fixed the problem. I bought it from Solo Auto Electronics (http://www.solopcms.com/). They offer a lifetime warranty standard, and their tech made it a point to talk to me on the phone to make sure I had fixed the wiring that caused the failure (so I not to burn up a second PCM). Shipping was fast. Really a good company.

 

Great info and pics. Thanks for the explanation and taking the time to post the pics. They will help many.

Just too bad Chrysler didn't see fit to use something like this in the first place. A simple thing that would increase repeat customers.