Bought the 09' Crew with the 4.7 in July. After the first fill up (420 miles), the engine light came on. Stopped and checked everything I could, drove home and called the dealer. They said I most likely did not turn the gas cap enough and they would check it.
1. First visit to dealer - After 2 hours the tech came back with a jar full of gas to show the advisor. He stated that the gas I put in is about 50% ethanol and the numbers are all over the place. Since the engine seems OK, use the gas, fill it back up and after 40 start/turns off it should reset or bring it back and they would. After 3 weeks (1700 miles), I made an appointment to come back since the engine light is on still.
2. Second visit. After about 1.5 hours, the tech felt the wires to the 1st and 2nd O2 Sensor was bad, when the moved them the engine light would go on/off. They reset it and made the computer differentiate between them. When the engine light goes off and bring it in. I got in the car, started the engine, light came on , so I drove to the service area and said its on.
3. After about 45 minutes, the service advisor came back and said they would need the truck for a day to address those 2 wires, or replace the whole wiring harness.
4. 4th visit. Dropped truck off, and came back at the end of the day. PCM board diagnosed as the problem, replaced and so far OK. Anybody else with this problem on their truck?

Other noted differences since PCM changed:
1. A/C compressor louder.
2. Fuel mileage increased from 17.6-19 City/Highway to 21-22.7?
3. Transmission not as smooth?
Chris

 

I would notify chrysler. Have one of their regional guys come take a look. They are the ones that look at an undiagnosable problem, take a bunch of data and talk to the engineers. Te engineers decide how to fix it, it gets fixed that way. The results are sent back to the engineers, they decide that it has been resolved. It would sound to me that the flash in the PCM either is wrong or it's just got all the new stuff that changes it. I'll bet it's wrong. Sounds like it's running to lean, if dodge could average those numbers safely they would have.

 

Where did you get gas that was 50% ethanol?

Edit: Arn't all of the 4.7 flexfuel anyway, shouldn't it not care and adjust for ethanol content, just as if you had e85 in the tank still, and then filled up with regular gasoline

 

Welcome to Dodge ownership!

 

Ac compressor 'noise' should have nothing to do with a PCM. PCM does have to go through a relearn which might take 50 to a couple hundred miles of driving for trans shift and might even change the MPG indicator.I had a re flash on mine and when I left the dealer it was reading 24 mpg.Took mine two days to settle in and shift/run back like it was.Update us on what its doing now?

 

Since the 4.7 is flex fuel, I would think it should have no problem with 50% ethanol. but it doesn't sound like that was ultimately the cause.

The A/C compressor shouldn't be affected by a new PCM.

Any updates on the trans and mpg?