Salaam aleikum everyone.
The problem:
After cold start, as soon as engine approaches operating temperature (temp. needle almost in mid position), the CEL lights up. Showing the TE1 to E1 shows code 52.
AFAIK that is for knock sensor (if something else, do tell please).
Suspects:
- Knock Sensor bad
- Knock sensor wire bad
- ECU bad (??)
- Code 52 meaning misinterpreted
What I've done about it so far:
- Tested the knock sensor for internal short. No continuity on multimeter, so I concluded it's ok.
- Tested the wire harness for continuity from connector to connector. It's fine. I conclude no breaks inside.
- Hooked up a signal obtained by backprobing from ECU connector, using a PC oscilloscope. Tapped the engine block and it showed a signal was produced. Started the engine and the knock sensor wire definitely had signals coming through it. So I conclude the sensor and wire harness both are ok.
- Drive test and listened to knocking by putting car in high gear as at low speed. Audible knocking happens once or twice, then it seems the ECU is compensating by retarding timing.
Have I done the testing right? Can the ECU itself be the problem here? Our have I missed anything or concluded anything wrong?
