Engine Management Light

[jcliff]

Hi All

I have a 96 1200 8 valve Corsa on which after driving a few miles and then braking on a down hill gradient the EML light comes on. The diagnostic report indicates idle speed control valve failure. I have removed this, cleaned and refitted and after resetting the ECU the smae problem occurs. Is this a common indication of complete failure of this part. There appears to be no engine or running problems with the car when the EML light is on and switching off the engine and re-starting will extinguish the light

Any help will be appreciated

Many Thanks

[haydn1987]

ussualy when the idle control motor goes you will find that the car will rev it self or the revs will die and stall the engine, this is ussualy fixed by a good clean with carb cleaner.

If your engine is running and idling fine then its unlikely the part has failed, I would check the wiring for damage or loose connections.

how did you test the fault code did you use the paperclip test or a proper reader?

[jcliff]

Hi

The codes were read at a local garage on quite a sophisticated using a diagnostic machine

Regards

John

[haydn1987]

Its difficult do diagnose a problem when you say it doesnt effect the engine when the light is on.

How often has the light come on and is it only while braking down hill?

A fault with the idle control motor is only noticeable while the engine is idling which is why you may not have noticed any problems. next time it happens press the clutch and see what happens to the revs if they shoot up or drop realy low then its definately a problem with the idle control motor.

here is a guide to the paperclip test where you can check for fault codes yourself
http://forums.corsa-b.co.uk/viewtopic.php?f=105&t=11231

[hoody99]

i had the same problem and it turned out not to b the idle controle valve it was a loos conection from the large plug located infront of the battery try tapeing up the wiers on it so they cant move and also i have the egr system on the manifold a clean and its never came on since

[jcliff]

Hi

The fault does happen more often when braking on a downhill gradient but has happened ocassionally when just driving along

I will have a look at the large plug at the weekend

Thanks

[hoody99]

well wen it happend to me it was wen i was slowing down to and my battery wasent very secure at the time so it was knoking the plug so a dont think that helped but its worth a try let us know how u get on bud

[jcliff]

Hi all

I have changed the valve for a brand new one and yes it is still the same. I have noticed that sometimes the light now goes off of its own accord. The snap-on diagnostics still reads it as a idle speed control valve fault so any more help would be most appreciated.

Thanks in advance

John

[haydn1987]

If it still does it with a new part then its probably some wiring or a connector that has broken that you can't see follow the wires for the idle control motor and check for and sign of damage and check the connectors.

Is your throttle stiff or stick on it could be that the idle control motor is having trouble pushing the throttle.

It could be that another sensor is giving false readings and the ECU thinks the idle conntrol motor is dodgy, check the throttle position sensor give it a spray with carb cleaner and check the connection. Check the Map sensor wiring and connector also make sure the tube is clear.