Ive been doing a lot of searching on this code and it seems there are a few different things that trigger it with my circumstance maybe being the most common. Truck runs fine, no engine light at start up, good power. However, once warmed up I will get a knock under load and then a short time later another knock under load which throws an engine light.
Based on many Google searches it appears this may be the result of a defective sensor. I’ve read several posts suggesting that once the coolant reaches a predetermined temperature the ECM tests the knock sensor by advancing timing until a knock is detected. If no knock is detected it performs the test a second time and if no knock is detected throws a light and a code. At this point the truck feels like it loses power and gas mileage sucks(10 mpg on a stock 350/700r4 with stock tires). Is this the ECM retarding the timing to prevent knock because of the knock sensor code?
I’ve got a new plug and AC Delco sensor on the way to swap in. The person I bought the truck from told me this code started showing up after he changed the starter. It seems logical to me the plug and/or sensor may have been damaged during starter replacement. I will update this thread when I have it swapped in.
Based on many Google searches it appears this may be the result of a defective sensor. I’ve read several posts suggesting that once the coolant reaches a predetermined temperature the ECM tests the knock sensor by advancing timing until a knock is detected. If no knock is detected it performs the test a second time and if no knock is detected throws a light and a code. At this point the truck feels like it loses power and gas mileage sucks(10 mpg on a stock 350/700r4 with stock tires). Is this the ECM retarding the timing to prevent knock because of the knock sensor code?
I’ve got a new plug and AC Delco sensor on the way to swap in. The person I bought the truck from told me this code started showing up after he changed the starter. It seems logical to me the plug and/or sensor may have been damaged during starter replacement. I will update this thread when I have it swapped in.