Anyone wash (degrease) the engine recently??? If so thats the culprit, water got under the intake manifold and shorted out the knock sensor(s)..... Been down THAT road on my last H2. After costing approx $450 to correct, I no longer degrease the engine in a uncontrolled water fashion....

 

i use a pump up sprayer to detail the engine. like the ones you get at home depot for weed or pesticide.

 

Well, my husband drives it to and from work and told me just now that the light was short lived. The light popped on on Friday and was still on when he went to work on Saturday. However, he said that Saturday after work the light was no longer on and hasn't been since. I don't know if the mechanic had washed the engine or not. If in case it was a fluke is there an additive I can add to the tank to help guard against it?

 

maybe it was just bad gas. use top tier gas when you can if not available locally https://toptiergas.com/licensed-brands/ GM used to rebrand chevron techron i dont know if they still do as a fuel additive but most top tier fuels already contain there own blends

 

That could be. We use Sam's Club and that is the only one not on the list around us. Thank you for the advice. I'll definitely be changing my gas selections.

 

Knock Sensors, Catalytic Converters (2), and O2 Sensors are pretty common items that at this age sooner even of the vehicle will start to fail, at 2k for catalytic converter repair sounds reasonable if they used OEM GM converters and both of them and that it included the O2 sensors.

 

sam is correct https://www.gmpartsgiant.com/oem-hum...converter.html and that is a sale price if they also used OEM oxygen sensors which would be 4 plus exhaust gaskets the mechanic used most of that money on parts with maybe 2 hours of service time for a somewhat profit of maybe 300 or a bit more not much more though. but that is if all OEM parts where installed but even the aftermarket parts are still costly.

 

Thanks, Sam! and bronxteck. I appreciate the help. bronx, Chevron does market the Techron as an additive still. I'm going to buy some today and then for each oil change.
https://shop.advanceautoparts.com/p/...B&gclsrc=aw.ds

 

Well, this was all short lived. After the check engine light went off and we filled the tank with TopTier gas and thought our problems were over for now. Well a week ago while driving, the dash started beeping and all the panel lights came on. Things stopped but the check engine light stayed on. We've driven it two more times and this same thing has happened each time. Today I ran my FIXD scanner on it and it gave me two codes. The P0332 Knock Sensor came back on and the second one was P2135 Throttle/Pedal Position Sensor/Switch 'A'/'B' Voltage Correlation. For the first code do you think I can get away with adding the Techron additive mentioned above? Would that maybe fix that code? And the second code, just what is that entail?

 

for both issues knock and throttle body you need to start by looking at your wiring harnesses. they are located very close to each other. you might have something rubbing through and now it may be getting worse since it is affecting the throttle body as well now. you can also check your throttle body for carbon buildup or foreign debris.