Replaced EGR sensor, reset PCM?

[Eric1971]

1995 4.0L OHV: I just reset PCM last weekend when I put in new plugs and wires. This week it's felt like power and MPG were LESS than before the plugs and wires so I pulled the EEC codes and sure enough I had some EGR errors (335 and 336). I did some additional troubleshooting, enough to be confident it was the EGR sensor, so I just swapped that out today. Boom, error codes gone. Nice to see a 111! Drives and feels better now.

Just wondering if I should reset the PCM again or if the EGR sensor would have no effect on that.

 

[fast_dave]

@Eric1971

Yes - definitely reset your X's computer and welcome to the forum!

 

[J_C]

First off, unless you were getting misfire codes and wished to clear them, there was no reason to reset the ECM upon a spark plug and wire change.

Some people may advise it is always wise to disconnect the battery when doing any work, particularly electrically related, but once you do, the ECM must go through the learning process again and it is expected you will get lower MPG until that happens.

An EGR sensor fault can cause loss of power and if a code is set that should be cleared from the ECM but again having done so, you will be running rich until the relearn procedure is complete and suffer lower fuel economy until then.