2000 Corolla intermittent engine light

BOSTIK

Little issue with the engine light intermittently appearing (not flashing) on my wife's Corolla. Disappears then mid cycle after a couple of drives, I was surprised at this but it happened when I was driving the car so I know she's not raving. Mechanic's scanning tool detects nothing in fault history after light has disappeared, fecking thing has never stayed on long enough for me to get it checked when it's lit.

So it's a 2000 VVTI Corolla saloon with 164K on clock and was serviced at about 158K. Was NCT tested just after last service and passed with no issues. It drives very well, especially on open road. She uses it mainly around town and says that the light mainly appears if car is stuck in traffic for a while. No hesitancy on idle that I'm aware of, the engine is not liable to conking out or anything. It gets a decent spin about once a month and she says it usually drives better after that.

Anyone got any ideas? The light disappearing during a drive is what confuses me most, I'd not seen that happen before though obviously I'm far from an expert in engine matters.

BOSTIK

Would this thread be more suited to the main forum maybe?

punisher5112

Honestly I wouldn't worry about it, it's most likely from the short drives and could well be a battery issue as not getting good enough drives.

It could be like the fuel mix and air etc is a bit off and then gets a good run and sorts itself out.

BOSTIK

Cheers, punisher.

I'm more curious than concerned really. NCT time isn't too far away so she'll have to get a good dose of the right foot then.

Mad_Mike

Its an odd one alright
The fact it happens mainly at low speeds around town would make me think either a charging/alternator issue or more likely, something like oil pressure.
Definitely keep an eye on it and try track down when it happens more often
In case it's related to oil pressure, at least make sure the oil level is well up
If you have a multimeter, stick it on the battery terminals at tickover, and also when revved up and see if your voltage changes much
If an alternator is working well, it should give maybe 13.5 to 14v at tickover, and increase very slightly when revved

BOSTIK

I hope it's not oil pressure related anyway. I know these yokes get thirsty for it with their VVTI engines so the oil level gets checked fairly regularly.

It got a new battery back around October-November.

joujoujou

Get yourself an ELM327 or something similar and smartphone app. Once light's up, it'll tell you what's wrong.

CJhaughey

Could well be related to the VVTi oil solenoid on the head, if they get dirty they can trigger the EML.

BOSTIK

Drove her to Dublin at the weekend so she got a mix of motorway and urban driving, no sign of a light.

My wife says that it generally doesn't appear if the car has more than half a tank of petrol on board, not sure how reliable that info is though.

Thanks for the tips anyway lads, hopefully I'll get to the root of it.

BOSTIK

So a few months later I find out that it's the exhaust oxygen sensor, apparently triggered by just driving short trips. Might never reappear if it gets a bit more long use. Nothing terminal anyway.