My sons commuter car is having an intermittent engine light. If you turn left while driving it goes off, turn right it goes on, move the wheel left and right you can make it a disco light on and off. I have had two code readers on this car and there are no engine codes. Im in California so it cant pass emissions test with any engine light despite the fact there are not codes. Any ideas are appreciated.
Very perplexing! If you could post a schematic of that section of the wiring, that might bring forth some ideas. Those dash lights are often powered all the time the key is on, on one side, and when the engine computer wants to light one, it grounds the other side, causing current to flow and turning it on. Perhaps there’s a short circuit in the wiring harness that is bypassing the computer harness, shorting out the other side of the CEL, and turning it on. That would explain why there’s no codes being stored. A quick look-see under the dash might help. Are there any wires moving around when you turn the steering wheel? Look on the other side of the fire wall too. It could be a problem inside the steering wheel or steering column, like the clock-spring. That’s a common place where shorts can occur from comments here. The clock-spring is a flexible gadget that allows wires to go into the steering wheel from the chassis, and still allow you turn the steering wheel. I wouldn’t guess the CEL light would be involved with the clock-spring, but anything’s possible I guess.
Left turn only for emission check? Codes should be stored, my guess bad motor mount causing stress on a harness.
Thanks for both replies i will check under the dash and outside firewall. Good idea on the motor mount too, ill check were not rocking the engine back and forth stressing a connection. I double checked the engine for codes, nothing shows up at all. I tried a cheap odbII and a high end reader, both come up clean even with check engine light on.
You might have a loose connection to a sensor somewhere, another idea. As I recall on my Corolla if I forget to plug in the coolant temp sensor when buttoning up after doing a fix, the CEL will stay on after I start the car. But if I stop the engine, reconnect it straight away, start it up again, the CEL turns off, and there are no codes set indicating there was ever a problem. The Corolla is OBD I, not sure if that is possible for OBD II like your vehicle probably is.