So my girlfriend has a 2008 Saturn Astra XR. If you are reading this second sentence, thanks for sticking in there, hahaha.

So it threw a P0068 TPS measurment out of tolerance yesterday. But there was absolutely no difference in its performance. It knows where the Throttle is and is supposed to be. Today after driving it around pretty hard (without her in it) it added to the mix a P1101 MAF measurment out of tolerance. So that with the other leads me to believe that it is the PCM reading them wrong. I opened up the intake and checked it for clogs. Disconnected everything and cleaned the connectors and reconnected it all. I cleared the Codes and we have been taking the Mazdaspeed3 around since then. So I havent had a chance to check it out to see if I can recreate the codes. My question is how can it throw those two codes without changing the performance or drivability? My only guess is that either PCM is reading it wrong in the logic circuits that compares the two signals coming from the MAF and TPS. Or amazingly both the MAF and TPS went bad at the same time to send the wrong signals but not affect the drivability.

Any thoughts?

 

intermittant problem - maybe a moist or dirty or cracked connector? Sunspots?

 

it could be in "limp home mode" driveable, but not to the ebst of its abilities. Are you getting worse gas mileage? the limp home mode usually just overcompensates by throwing in a crap load of gas to make sure it doesn't run lean when certain sensors fail..

 

I dont think it is a limp mode, there is zero change in its drivability. There is no smell of running rich. I have had a PCM go bad before, but the car showed serious symptoms that something was wrong. THis is just perplexing.

 

The only explanation I have, other than the rare coincidence that both TPS and MAF went bad at the same time, is that something got into the wire loom and bit a few wires. As for not being in limp home mode, maybe the ECU is still able to tune it properly with less sensors, as it knows the two are "bad" ? Have you tried checking voltage outputs of the TPS? It should read between 0-5V throughout the range (typical setup). If its giving you a proper output, I'd follow the wire loom or check to see if you can swap ECUs with someone