I'm having issues getting my car fixed and I'm hoping someone on here may have an idea whats going on. About 3 weeks ago my check engine light came on with codes P0103 (something with the MAF) and P0327(engine knock detected). I took it to a local chevy dealer and they told me it was a bad drivetrain control module, and after a week of waiting I finally got my car back. Never mind the fact that they charged my $200 more than I was quoted, or that my performance tune got wiped out in the process. I drove it a few days later, maybe 50 miles total, and the engine light comes back on. Now it's throwing codes P0327 and P1154(something to do with oxygen sensors). Does anyone have any idea what could be causing this? Obviously it wasnt the computer they replaced. I do have a small exhaust leak on my left header, could this be part of it? If it werent for the fact that I'm going to insist they fix it for free I wouldnt be taking it back to the same dealer. Someone please help!

 

Well, the P0327 is a knock sensor failure. There are two of them. You will need to remove the intake to replace them...yes, buy and replace both at the same time. I will guess that knock sensor to the PCM is either non-existent or flaky to the level that the PCM flagged the error code. I've read that the front one will get contaminated with water causing the external area of it to build up deposits which then cause its function to degrade. Tehy are basically microphones that are designed to listen for detonation. When its heard, the PCM retards the timing. Taking this a step father and I really am not sure here, if the timing stayed retarded for an extended length of time, the timing might possibly mess up the O2 sensors making the problem even worse.
DTC P1154 HO2S Transition Time Ratio Bank 2 Sensor 1, I'm not the best person there. Try sending a PM to Bill Dearborn.

 

Sounds like it makes sense though, thanks. Anyone else have any ideas? I'm trying to give the dealer some ideas of what else it could be. Not my job I know, but if it gets them on the right track...

 

First of all, sounds like the dealer you are using did not thoroughly diagnose/fix your problems since the knock sensor DTC was not resolved after the PCM was replaced (if it was). That fault would still have been present if the only thing replaced was the PCM. Also, replacing the PCM is often the "Hail Mary" of fixes when they either can'y figure out what's wrong or don't feel like going through all the diagnostics to find the problem. The manual has detailed procedures for sorting out the issues you're experiencing.

The P0103 DTC could have been a number of things that would have caused the PCM to see excess intake air including a leak downstream of the MAF or moisture in the MAF sensor or AIR system which overcooled the sensor wires. Intermittent failures can be triggered by a mis-routed harness, rubbed through wire insulation, broken wire inside the insulation or a poor connection in the ignition feed circuit to the MAF sensor. Replacing the PCM is the last suggestion at the end of the diagnostic.

The P0327 DTC is similarly diagnosed with a sensor replacement advised well before the PCM is swapped. There is more likelihood the sensor went south before the PCM.

The P1154 DTC indicates a problem with the front passenger-side oxygen sensor in the exhaust manifold that could be caused by an exhaust leak or a bad sensor. Check for leaks first and then test the sensor. Contamination from fuel, use of improper RTV sealant and engine oil/coolant consumptionare are often causes for O2 sensor failure. The manual has a detailed diagnostice for this and PCM replacement is not a remedy.

Start using these checks and you should be able to resolve these problems.

 

Thanks guys, I appreciate the help. And yes, this will be the last time I use this dealer. Not the first time I've had issues getting things fixed with them.

 

Fix the leak, clear the code and see if it returns...

 

 

I had the same problem with the P0327 about 6 weeks ago. Upon removing the intake manifold I noticed the rear knock sensor sump was full of oil. Also when I went to remove the harness connector from the front sensor the sensor itself broke (plastic piece broke off). I discovered the rear knock sensor rubber seal had fallen out so I repressed it in, installed two new knock sensors, check the harness for conductivity where it passed and reinstalled the harness. I reinstalled everything and nearly immediately it threw the P0327 code. This eveing I began removing the intake manifold again I found the rear sensor had the beginning stages of oil migration on the top of the sensor, the front sensor looked brand new. Also I rechecked the harness for conductivity and found nothing wrong.

Because of all this the only possible thing that I can think of that is the culprit is the harness to sensor connection is not of good quality and therfore causing the sensor to throw the code. Does that sound like it could be the culprit? What about the oil migration on the rear sensor?

 

Did anything ever come of this?