Poll: What is causing the check engine light to go on?

[shaginator]

Thought I'd have some fun with this polling feature...

1994 Q45 131,000 miles- Starts fine- Idles well- Runs great- Check engine light only goes on after cruising about 10-15 miles. Goes on sooner during highway driving. No impact on engine performance.- Once the light is on, if you park and then come back... light is off again.- Goes back on again after a few miles of driving.

I reasoned it would be the O2 Sensor. But I'm no expert.

I plan to check the ECM tonight to verify the results

[DAEDALUS]

There's no knock sensor error code? I vote knock sensor and/or leaky injector.

[shaginator]

if knock sensors is part of the MIL, i'd put it in, but i can't edit the poll now.

[PalmerWMD]

if knock sensors is part of the MIL, i'd put it in, but i can't edit the poll now.

I can, knock sensors going in.

Fred..

[shaginator]

The self-diagnostic (mode II) showed code 34 (knock sensor circuit). I took apart the harnesses and there was one bent wire out of the two that sit in that top clip thingy. I also dabbed a teeny amount of dielectric grease on the contacts and then re-connected.

After that, I got code 55

Running the O2 test, ECM reports a problem with the right-bank O2 sensor.

Hey, you guys are good!

[Mayhem_J30]

Good job Shag!