Hello - 86 berlinetta - my service engine light came on, and using a paper clip i retrieved code 21 Throttle Position Sensor. I was skeptical because i don't notice any performance symptoms - starts up fairly easy when cold, accelerates fine, idle is smooth. So I disconnected the battery to "reboot" the system and see if that would clear the light. Not only did it not clear the service engine light, but now my dome light and kick panel lights won't turn off. Could i have shorted something out with the paper clip? Could disconnecting the battery cause those lights to stay on? Is it possible the service engine light was coming on for no reason? Any feedback would be great!

 

Most likely this is a coincidence and it's just the door ajar sensor. The sensor is in the front of the door jamb on the body side and grounds out when the door is open. So either the sensor is bad (easy $4 fix) or the wire is grounding out somewhere.

 

You didn't short anything by checking with the paper clip - at least you didn't as long as you put the 2 ends of the paperclip in the proper terminals !

The interior courtesy lights are on a timer - so be sure that the key is turned to OFF & the doors are closed for a minute or 2 so the interior lights have a chance to shut off before investigating. If you sit in the car and wait for a minute or 2 you should hear the Light Module "click" and the lights should turn off. If you hear the click and the lights do not shut off - then try to use the button on the roof console to shut the light off. If still no luck; I'd unscrew and check the door switches at the front of the door opening. It's possible that one of them is causing the interior courtesy circuit to become active. ( switched ground signal ) Another possibility is that the roof console wiring is messed up; not common - but possible. The other thing that could cause this problem is a failing Light Module.

 

thanks guys. I checked the codes again and now in addition to code 21 I'm also getting a code 13 O2 sensor, which I saw a video that claimed a malfunctioning throttle position sensor can trigger a O2 sensor code - agree?? It would further validate getting the code 21...guess the only way to know for sure is to check the voltages - the supply should be 5v and the return range about .9 to around 4.9, correct?

on the dome light - the roof console button doesn't do anything so obviously there is something wrong with that (however the map light button does work) - any tips on popping roof console opened? I've got Ttops with the little built in flash light, storage pouch, and manual trip counters...

 

Pop the dome cover off, unscrew the 2 screws hidden under the dome light cover, then push the entire console forward. ( it slides onto 4 pre-mounted studs ) Once it falls off the studs,... unplug & Done.