Today my CEL came on, and my reader reports a P0850 code. The car seems to run fine.(Maybe a little bit of hesitation around 3000RPM? Or maybe I'm just imagining it...) I've seen a lot of other members reporting weird idle RPMs (and worse!) when this code appears, so I'm not sure if the sensor is truly dead, or if it's some kind of intermittent electrical problem.

I recently wired some extra LEDs into my headlights, splicing into the parking lights (the innermost bulbs in the headlight, which come on when the headlight switch is turned to the middle position) right near the bulb, and I'm wondering if the two might be related. The lights still work fine.

I'll get under the car and test the sensor later this weekend, but I figured I might as well ask on the forums now: Does anyone know whether a short or disconnect in the parking lights' wiring might be setting off a P0850, or are they definitely unrelated?

 

I'm taking the silence after 40+ views as an "idk man, maybe", which is about how I feel about my question too. A short anywhere could mess with the car's ground a bit, but the lights and the transmission sensors are pretty obviously on different circuits, so it seems pretty unlikely that they were related.

In any case, I tested the sensor last night and it seemed to work fine, so I blew some contact cleaner into the plugs, hooked it back up, and cleared the code from the ECU. I've since gone about 40 miles and so far the light hasn't come back on, so I believe it's fixed.

 

Don't know. P0850 usually to do with neutral safety switch or a dirty ESPS. Never heard of parking lights causing an engine code.