Knock Sensor Blues!

Bryan81 · December 4, 2008

I just got an 03 Tahoe Z71 with the 5.3L engine. I was getting the usual P0332 code for the rear sensor. I replaced both sensor's and the harness. Now I'm getting P0327 and P0332! I check both sensor's at the computer and they are reading 98 ohms. I tried a new map sensor with no change. The truck has no knock or pinging at all and runs great but I keep getting the code. Could it be the ecu itself?

Thanks in advance!

Bryan81 · December 6, 2008

Any ideas at all......anyone?

Draenor · December 6, 2008

1) The replacement KS is defective.

2) There is a bad connection or short between the KS and the ECM.

3) The KS is loose or possibly overtightened.

4) Worse case...The ECM is bad

Thats about all I can think of. BTW, just because you do not hear the pinging does not mean there is no pre-detonation going on.

Zembonez · December 6, 2008

Thats about all I can think of. BTW, just because you do not hear the pinging does not mean there is no pre-detonation going on.

+1

The knock sensor is designed to detect knock long before you would ever hear it.

Bryan81 · December 6, 2008

Well the rear sensor was definately bad which is the only one that was setting the SES light origionally. Then I replaced both sensor's and the harness, torqued them to factory specs and both sensor's are show low input. They both ohm out to factory specs so I don't think they are bad. The only thing I cannot test or don't know how to any way is the ecu. I put octane booster in and ran 93 octane gas with no difference. I took the intake off and checked everything again, made sure they had a good ground cleaned everything up again and no difference.

Can I just try another ecu or do I have to have it programmed to the truck?