cel light on startup
 

i have recently bought an esl v3/4 and when i start up the cel light stays on until ive drove down the road, about 100m and then goes off, its done this since ive had the esl. ive done a cel check and its giving me a code 22 (knock sensor). the knock sensor is about a year old so quite new.

previous ecu was a powerfc and the knock readings on there used to work as should, car drives as normal apart from that. a bit worried its not retarding the timing if it needs to.

any ideas??

cheers steve

It's done it since the ESL was fitted because the Apexi doesn't have diagnostic control code capability and doesn't use the knock sensor for active control.

If the CEL extinguishes then it will run active knock control as normal. If it stays illuminated then it will pull the IAM and the car will feel down on power.

Check the knock sensor is properly attached and torqued and the wiring is sound. If the problem persists swap the knock sensor out for a known good one.

If you have the ESL software and cable you can monitor and reset all fault codes from software. You can also log the cyclical knock count and IAM and IAM search step to help aid diagnosis.

Why was the sensor replaced a year ago?

thanks for the reply andy.

yeah i know the powerfc only can read knock but it seemed to work fine.

put my mind at rest though i was getting worried that the ecu wasnt able to detect knock if it was giving me a code 22

yeah the sensor was replaced about a year ago. as said it does it from cold on start up, could it be detecting slap maybe.

when the ecu does detect knock what kind of cel does it throw up, i know it does back off timing when detecting knock but wondered if it tells you.

cheers steve

I would get a mapper to have a look, if its picking up slap it could be pulling timing which will reduce power, the sensor may need re scaling to cope with the cold start slap ect.