OVP Relay - 190E 2.0 Auto

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nullogik

Active Member
Joined
Apr 29, 2008
Messages
456
Car
1993 190LE, 1994 190LE, 1998 S420
Hi,

I'm looking for a new or used OVP Relay for a 1993 Mercedes Benz 190E 2.0 Auto.

The part no is A2015403745.

Please PM me or post a reply if you have one available.
 
Hi Nullogik,

Is your one faulty? Normally they just need resoldering, probably worth trying first :)

What symptoms do you have?

If not, I may have a spare at home, I'll check for you later.

Is yours the single or double fuse type?

Will
 
I've got a very rough hot idle and hard starting when hot.

Looking at previous posts I've seen that the OVP is sometimes a cause of this problem.

I don't know whether its a double or single fuse type - I was just given the part number by a Merc Dealer. How can I tell which one it is?
 
You need to check the old one first. It's located behind a plastic panel, behind the battery near the bulkhead on the N/S (passenger side)

Is your ABS light on?

You can measure the voltage drop through the relay if you suspect it.

I would personally perform some other diagnostic checks before you start replacing parts :), this invariably doesn't solve the problem quickly and will cost you time and money.

Will
 
Thanks partsspecialist. Thats the price that Inchscape quoted me, but since I'm not sure its the OVP at fault I'm not keen on spending £60 and it doesn't fix it - which is why I'd like to try a secondhand one first.

The ABS light doesn't come on.

Sorry, if this is a stupid question, but can the voltage be checked when the relay is out of the car? And what figures are "good" readings? As you can see, I'm not very good with electronics.
 
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As Will says the problem is often dry joints on the base printed circuit board. You have to remove the can first. and then go over all the soldered connections remelting them with a soldering iron. Any electronics guy/local amateur radio enthusiast could do this for £5-10 / a couple of pints. Perhaps worth a try?
Good readings are a negligible voltage drop across the relay- ie 12 volts DC in at the supply terminal -- 12volts DC out at the outputs when disconnected from any load.
 
Thats a great help Grober. I think I know just the person who might be able to do that for me and its certainly a lot cheaper than a brand new OVP.
 
As access to the OVP is not brilliant, you can quickly check that the OVP is working by checking the voltage drop between battery positive, and the red/yellow wire on the ABS unit while the engine is running.

Suspect the OVP if there's a significant voltage drop.
 
Thats a great tip, it will save wrenching the thing out.
 
I can get you one. Its not a MB one (does not go wrong!)


£40 to you sir.
 
billy_whizz, you have a PM.

Thanks!
 
As access to the OVP is not brilliant, you can quickly check that the OVP is working by checking the voltage drop between battery positive, and the red/yellow wire on the ABS unit while the engine is running.

Suspect the OVP if there's a significant voltage drop.

Managed to get hold of a multimeter and the voltage difference between the two points (as mentioned above) was 0.02V. I think this is a small drop, so the OVP might be OK.

Thanks to all who helped.

PS. I chucked some injector cleaner in before a trip down the motorway and that seems to have helped smooth out the rough idle somewhat.
 
Try cleaning out the throttle body and idle control valve with some carb cleaner before looking at anything else.
 
That will make a nice Saturday afternoon job Dieselman if the sun stays out, I'll definitely look into it.
 
Whilst you're at it, check for any vacuum leaks into the manifold.
 
I would consider myself as a novice mechanic, would cleaning out the throttle body and idle air control valve be something that someone with basic knowledge be able to do?
 
If you can point a screwdriver you will be fine. If not..:eek:

The throttle is ITEM 89 so you will have to press the intake air plate (in item 44) down to gain access to spray it.
 
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I hope so :p, I'll need my glasses on to see where I'm pointing though!

Thanks Dieselman
 

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