CEL - what to do?

Silvia · Postby **Silvia** » Sun Apr 13, 2014 3:40 pm

Driving along today as normal and CEL comes on so I stop and check things - all vital signs are fine. Drove on home.
Engine km 87k young and nothing modified and normal servicing.
Only thing of interest is when ignition is turned on the CEL stays off for a moment then lights - probably normal?
So what is best course of action? It's just before Easter (of course) and Mazda dealer is 30km away...

Sailor · Postby **Sailor** » Sun Apr 13, 2014 4:52 pm

Buy a cheap OBDII reader and look here for diagnosis and advice on fixing it.
Plenty of good ones on ebay.

The reader will also clear the code and it might never come back...even a loose petrol cap will throw a code

http://www.samarins.com/diagnose/codes.html

Silvia · Postby **Silvia** » Sun Apr 13, 2014 5:44 pm

I need to use the car and can't wait for ebay.
Looked at the net and found an article on resetting the CEL - involves the ol' disconnect negative lead from battery for 5 mins . Too early to say , but CEL has gone out now, but haven't dríven only idled.
I had put a trickle charger on for a week to top up battery, wonder if this had anything to do with it?

Jeo · Postby **Jeo** » Sun Apr 13, 2014 6:21 pm

Disconnecting the battery for a few minutes should reset the ECU, which will fix the problem of the light being on. Won't fix the potentially terminal engine problem that caused the light to go on in the first place, but it will fix the problem of the light being on for a while at least. Also I hear a small piece of electrical tape over the light does a pretty good god of fixing this problem too if you can't be bothered waiting for the ECU to reset. Carful though as after a while the tape can fall off which means you're back to square one.

Seriously though, CEL will throw a code that can help in diagnosing. If you don't have the equipment to read the code, take it to a shop that does. It might be something simple like the O2 sensor plug falling off, or it could be something far more serious. I'd want to know rather than just driving until it goes pop.

Silvia · Postby **Silvia** » Mon Apr 14, 2014 4:47 pm

Well today I drove to a mechanical repair shop and there was no sign of the CEL any more. :roll:

Ze good German mechanic said nothing to be done, bring it back if the light re appears. It hasn't.
He said a bad batch of petrol or high humidity could also be causes....as well as the obvious ones like oxygen sensor.

taminga16 · Postby **taminga16** » Mon Apr 14, 2014 5:06 pm

Silvia wrote:I need to use the car and can't wait for ebay.
Looked at the net and found an article on resetting the CEL - involves the ol' disconnect negative lead from battery for 5 mins . Too early to say , but CEL has gone out now, but haven't dríven only idled.
I had put a trickle charger on for a week to top up battery, wonder if this had anything to do with it?

If you have not disconnected the battery and your 'trickle charger' has experienced a surge there is a posssibility that it is all that it is.
Keep an eye on it.
Greg.