Engine warning light

[JonB]

Out on a shortish run today, only 6 miles or so, I notice the tickover is high, about 1200ish, no probs I think, just time to give the MAF a clean. Start up for the run home and the dreaded engine light stays on, not in a position to stop and check it properly so clenched my cheeks and eased my way home.
Did the dash dtc code check and it comes up with "none", and idle is back to 880ish, so will be generally going over everything tomorrow, checking connections, cleaning sensors etc.
Anybody got any ideas as to which sensors would trip the warning light without showing a dash code?

 

[JonB]

Cleaned MAF, opened every electrical connector in sight and used a bit of wd40 on them, reset ECU.
Result no more warning light, but seeing as ECU was reset had to do a selection of town poodling at 30 mixed with some more spirited driving down the lanes (where national limit applies, officer) only hit the rev limiter once, or maybe twice on downshifting.
End result is another warning light has come on..........the low fuel one, never mind I know how to fix that one!

 

[yippeekiay]

:thumbs:

 

[pumapilot]

If the EML (Engine Management Light) comes on and the car runs as rough as a bag of bolts, then you're in trouble, the ECU has put the car into "get you home" mode, which is 50mph maximum speed, and only use gentle acceleration to get you and the car home, then leave the car at home until the problem is diagnosed (might mean a trip to the nearest garrage) and sorted out.

If the car runs ok when EML comes on, then reset ECU by disconnecting battery for half an hour, reconnect battery, start car and let it idle for a good 5 minutes (let mine idle for 12 minutes today), EML should stay out, but if it doesn't, then get car checked on a diagnostic computer at a garage, unlocked dashboard might not show correct code.

 

[JonB]

Thanks pumapilot, she wasn't running rough and as I was in London and going home its 30 limit everywhere. I did the ECU reset next day and while battery was off made sure all connections were clean and pushed home. I did let her idle for about 10 minutes before driving around, I'm sure the procedure is on here somewhere. I guess she just wanted a bit of attention but am still none the wiser as to why the light came on in the first place. If she does it again I will get a plug in diagnosis, just wondered if there was a usual suspect that would trip it.

 

[pumapilot]

It only takes a blip of any sensor to give a reading to set light off, mine has been used as basically a shopping trolley over winter, ran to Tremona in Southampton ok mid January, been short runs since then, took a mate to an out-of-town pub midweek, and EML came on, must've blown a few cobwebs out.

Reset ECU as above - ok now.