[W126 Coupe] Suspect OVP relay (update)

[Afzaal Khan.M]

Great!  fault diagnosed and  rectified.
mak

On 16/06/2009, Vance Rowley <vance.rowley at tiscali.co.uk> wrote:

>

> Yes, at last, confirmed. Received my new OVP relay this morning and before

> the delivery truck had driven away, I had the parcel ripped open and fitted

> the relay. My thoughts as I was about to turn the ignition key was "well,

> here goes" But as soon as I did, I could tell that this is it, as the engine

> started immediately and the ABS/ASR warning lights went out. It used to take

> around 10 seconds or more of the engine turning over to start with the old

> relay. The engine was very smooth and no stumble or hesitation when revving

> the engine. The idle was fine also.

> I know that the OVP gets blamed for everything, but it looks like if you

> have the 4 symptoms all at the same time.

> 1. Takes a long time to start

> 2. High Idle

> 3. ABS/ASR warning lights remain on.

> 4. Rough running of the engine.

> Then it looks like the problem is almost certainly the OVP relay. Of course

> it is possible that the fuse is just blown, but if that is OK (as mine was)

> then a new OVP should be the next step.

>

> For those who want to have a go at repairing the relay, from what I have

> discovered along with input from this group, it looks like if you get all

> symptoms at the same time, then as long as the fuse, relay coil, contacts

> and solder joints are OK, then the most likely culprit is the diode

> connected between pin# 15 and the relay coil. It is unlikely that the zener

> diode is the problem, as this would more likely blow the fuse if the zener

> was at fault. If you get only 1 or 2 of the above symptoms, then a solder

> joint (or more) would be most likely.But of course when you get only 1 or 2

> of the symptoms, say for example the ABS warning light on, then it's

> possible the OVP is fine and that the problem could be the ABS computer

> itself. It's understandable that the OVP gets blamed for everything, but is

> certainly the first thing to check.

>

> Thanks again to everyone who gave their input.

>

> Regards,

>

> Vance.

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