Engine management light - no fault found 28 October 2022 at 3:46PM in Motoring 15 replies 787 views

Annie1960

I had the engine management light come on, and left the car in to the main dealer. They said there was no fault found, and no codes were stored. They didn't charge me, but said there would be a fee if it happened again.

Does this sort of thing happen a lot? 

SiliconChip

It's not unusual. When the EML came on in my car a couple of years ago the dealer that I bought it from new 5 years previously wanted to charge me £95 for just reading the code, a sum that would go towards further work should a fault be found. Instead I took the car to my local garage who plugged the reader in, did some looking into possible causes for the codes found, and eventually cleared the light, all for no charge. I took it back a couple more times when the light came on again and they finally discovered the underlying cause and charged me for a replacement vacuum hose. The lesson is to find someone who actually wants your business in the future rather than is in it to make a short term profit.

Bigwheels1111

Buy an OBD2 Code reader.
Just a basic £15 one will do.
Plug in read codes. Note down code.
Then erase.
Look up codes just in case they come back.
My car gives a code for faulty Nox sensor.
Clear code and off I go.

Annie1960

Bigwheels1111 said:

Buy an OBD2 Code reader.
Just a basic £15 one will do.
Plug in read codes. Note down code.
Then erase.
Look up codes just in case they come back.
My car gives a code for faulty Nox sensor.
Clear code and off I go.

Where would I plug it in?

DanDare999

Annie1960 said:

Bigwheels1111 said:

Buy an OBD2 Code reader.
Just a basic £15 one will do.
Plug in read codes. Note down code.
Then erase.
Look up codes just in case they come back.
My car gives a code for faulty Nox sensor.
Clear code and off I go.

Where would I plug it in?

OBD2 port, without knowing what car you've got, can't say where it is. 

Richard53

Just an aside: I had a fault on a Focus I owned briefly. It would throw the EML light on and go into limp mode whenever I accelerated hard. My OBD reader (a cheap Aldi one) showed no faults. The garage I took it to (used for years, 100% trusted) could see a fault when the car was driven but couldn't trace the cause, which would need a visit to a main dealer with Ford-specific equipment. I did, was quoted over £100 just to read the codes, THEN £120/hour for workshop time to fix. I took it round the back to their s/h sales office and traded it in the same day.

Just to say that home-brewed OBD readers will find most, but not all, faults.

forgotmyname

Battery voltage drops a little too low can trigger many faults or even running the fuel too low can trigger faults.

Issues from the enviroment, water spraying an electrical item in an exact way which is almost impossible to
replicate.

Had people complain of starting issues and found a pattern where it was people that started the car to move in or out
of a garage where it was running for under a minute and the cars had issues deciding if it was a warm or cold start.

Bigwheels1111

Annie1960 said:

Bigwheels1111 said:

Buy an OBD2 Code reader.
Just a basic £15 one will do.
Plug in read codes. Note down code.
Then erase.
Look up codes just in case they come back.
My car gives a code for faulty Nox sensor.
Clear code and off I go.

Where would I plug it in?

As DanDare999 said, make and model would help.

Some are easy to find some are not.

Vectra hide it under the ash tray and my Peugeot has it in the glove box behind a plastic cover. Took days to find it.

Others have it under the steering wheel above the pedals or under the glove box.

Annie1960

Richard53 said:

Just an aside: I had a fault on a Focus I owned briefly. It would throw the EML light on and go into limp mode whenever I accelerated hard. My OBD reader (a cheap Aldi one) showed no faults. The garage I took it to (used for years, 100% trusted) could see a fault when the car was driven but couldn't trace the cause, which would need a visit to a main dealer with Ford-specific equipment. I did, was quoted over £100 just to read the codes, THEN £120/hour for workshop time to fix. I took it round the back to their s/h sales office and traded it in the same day.

Just to say that home-brewed OBD readers will find most, but not all, faults.

I took mine to main dealer and they claimed there were no codes.

Annie1960

Bigwheels1111 said:

Annie1960 said:

Bigwheels1111 said:

Buy an OBD2 Code reader.
Just a basic £15 one will do.
Plug in read codes. Note down code.
Then erase.
Look up codes just in case they come back.
My car gives a code for faulty Nox sensor.
Clear code and off I go.

Where would I plug it in?

As DanDare999 said, make and model would help.

Some are easy to find some are not.

Vectra hide it under the ash tray and my Peugeot has it in the glove box behind a plastic cover. Took days to find it.

Others have it under the steering wheel above the pedals or under the glove box.

Vauxhall Astra, January 2020 model.

DanDare999

Annie1960 said:

Bigwheels1111 said:

Annie1960 said:

Bigwheels1111 said:

Buy an OBD2 Code reader.
Just a basic £15 one will do.
Plug in read codes. Note down code.
Then erase.
Look up codes just in case they come back.
My car gives a code for faulty Nox sensor.
Clear code and off I go.

Where would I plug it in?

As DanDare999 said, make and model would help.

Some are easy to find some are not.

Vectra hide it under the ash tray and my Peugeot has it in the glove box behind a plastic cover. Took days to find it.

Others have it under the steering wheel above the pedals or under the glove box.

Vauxhall Astra, January 2020 model.

Next to and slightly above the bonnet release.