Service Engine Soon

[touretteboy]

I'm all out of options.  I have a 2001 Chevy Silverado 3500, 6.0 V8 (RWD).  The service engine light came on a few months ago, indicating O2 sensors.  Replaced all four of them, including the mass airflow sensor (light went out for a few months).  Light back on, now indicating knock sensors.  Replaced both, including the wire harness.  Fuel pressure regulator may have been faulty, found fuel in its vacuum line.  Replaced both of those.  Light still on, indicating knock sensors (PO327 & PO332).  Truck runs fine, no stalling, rough idle, or acceleration issues.  Losing my mind.  Cleared codes, light came back on the next day.  Disconnected battery for 15 minutes, thinking it would reset computer; nothing helps.  What gives????  Thanks.

[davester]

If you google for those codes, you will find they don't say "just replace the knock sensor and the problem will be fixed".

 

You need to examine the connectors and wiring harness's between the knock sensors and the ecm.  It's also possible the ecm itself has a problem (but it's more likely a wiring/connector problem).

[Jac365]

I have 2001 camper with a 8.1 Vortec. Got  a check  engine light one day. Scanned codes..knock sensors. Replaced sensors. Good for a few days then CEL on again. Knock sensors. Eventually found that in my engine after market  knock sensors just wouldn't work. Replaced with AC Delco sensors, three years now so far so good.

[touretteboy]

I was replacing mine, got in a jam because the new torque wrench I was using was faulty and snapped one of the intake manifold bolts and also over torqued one of the knock sensors and caused it to spin in its housing.  Needless to say, I had to have it towed to a repair shop and have them finish the work (hundreds of dollars).  I told them to use AC Delco knock sensors, as I was using prior to the disaster.  I don't think they did.  The harness I used was ACDelco as well.  The only recourse I have is to take it back to them and find the problem, but it'll cost me more money, I know it.  They'll probably say the knock sensor they used is as good as AC Delco and won't replace it.  Any one have any experience like mine who, even after replacing with AC Delco parts and still had the CEL come on, found a fix?

[touretteboy]

1 hour ago, davester said:

If you google for those codes, you will find they don't say "just replace the knock sensor and the problem will be fixed".

 

You need to examine the connectors and wiring harness's between the knock sensors and the ecm.  It's also possible the ecm itself has a problem (but it's more likely a wiring/connector problem).

Thanks.  Will do.

[Formulabruce]

Also, While yours is drive by wire, its still  must be done. Remove the intake huge round intake clamp and housing, and Clean very very thoroughly the throttle body WITH Throttle body Cleaner ( not carb cleaner) This means Both sides of the throttle plate And housing. It must be spotless in there.

 You would be surprised how much a spec of black goo in there can do for codes.. I have done this many times on trucks for people and it does help even what it doesn't fix outright. Good Luck