My truck is an '09 Ram 1500 QC 5.7L with a 3.92 gear ratio, 53,000 miles. About a month ago the CEL came on. I've been having the local Autozone pull the codes and I've been replacing parts as I go hoping that at some point it will get fixed. I've also had the dealer look at, they were completely useless. The codes that are being thrown include:

P0138
P1129
P1128
P0152
P0132
P0138
P0058

All of these indicate O2 sensors, both banks, up and downstream, either a faulty sensor, or no power to heated sensor, and/or no closed loop on the entire bank. I've replaced both downstream sensors with OEM, the MAP sensor with OEM, and an OEM air filter. Currently the truck is throwing P1128/P1129, indicating no closed loop on both the passenger and driver side banks.

My mileage is worse by about 2-3 mpg highway. And just the other day my Oil Change Due indicator came on after only 2300 miles on the current batch of oil.

There's no way that so many sensors would fail all at the same time. I've started thinking its something further upstream, which is why I replaced the MAP sensor. Now that the Oil Change light is on, I'm thinking it might be the PCM/ECM. Problem with this though is that swapping a PCM/ECM is a heck of a lot more expensive than a $30-$50 sensor.

Nobody has an ECM/PCM matching the part # in my truck. Dealer said they reflashed the PCM but I honestly don't believe them. I really don't want to take it to another dealer because they are far more interested in bilking money out of you than fixing your problem.

Does anyone have any suggestion?

 

You should be able to turn the key to the position before start and step on the gas pedal all the way down 6 times to reset the oil change light to every 6 thousand miles.

For the multiple codes check the battery and make sure its good. You may have a bad ground somewhere. Check the ground wires attached to the body or frame.

 

I'd take it to a dealer and let them track it down. Throwing parts at it is a waste of time with that many codes, and it is unlikely that they point to the root cause.

If you want to check something yourself, pull the top off the TIPM and make sure all of the connectors are locked down on the bottom side.

 

I did take it to a dealer, they were completely useless. After sitting in the shop for 3 days they charged me $100 diagnosis fee to determine that the O2 sensor they sold me was faulty. They were going to charge me another $50 in labor to replace the same "faulty" O2 sensor. I bitched enough that they ultimately didn't charge me the labor to replace, but ultimately the light came back on.

I could try a different dealer, but at this point I have no confidence that they can fix this any better/cheaper than I can.

 

Personally, I'd try the dealer again or a well equipped garage unless you have the correct tools to test all the circuits and sensors. When the light came back on after their repairs did you take it back? There should have been a warranty on the repair.

If you are having autozone pull the codes then I assume you do not have the correct tools to do the job. I know it is frustrating but tossing parts at complex problems rarely does anything but costs $$$.

If you want to fix this yourself then you need a code reader, FSM and whatever tools are required for the test procedures in the fsm. IF you get a decent code reader then you'll also be able to see all of the readings from the sensors realtime. HAve a look at http://scantool.net

 

There is a TSB for the engine throwing O2 sensor codes, check with dealer, they obviously did not update the PCM, this TSB should cure the issue. Sorry I don't remember the TSB number off by hand.

 

Wanted to leave an update for anybody else that runs into this issue. After a total of 5 visits to the dealer and 3 months time it turned out that the problem was caused by the PCM. I had this replaced erlier this week and so far so good. Thankfully was also covered under warranty.