myth

iTrader: (7)

I need yall to brain storm for me. i have been fighting this for a week. Its a 5.3, 1999 pcm and 1999 wire harness. I have a 2002 silverado operating software loaded in the pcm. I am getting p0134 and p0154. I have tried two different oxygen sensors, grounded the high and low refference circuits and ohmed the wires going from the pcm to the oxygen sensors. The only thing I have found wrong is when grounding the high and low refference circuits. The pcm does not change mv's like it should.

I am leaning towards a bad pcm. But, do you think that the 1999 pcm using the 2002 program could be a problem?

Any help would be great. Thanks