OVP relay?

[Iain]

C200 sport auto 2000 'W' reg.

Rough running,not revving over 2500, disconnected MAF so it runs off ECU settings and still no change. I have read some posts which mention the OVP relay. What does OVP stand for? What function does it perform? and where is it located please?
All suggestion gratefully received.

 

[grober]

Over voltage protection -- OVP RELAY supplies voltage to the ECU but does other things as well --its fused at the top ---and is basically 2 relays and a circuit board in one casing. If its a year 2000 W202 its housed in the fuse/relay box in the engine compartment. about £60 from your dealer? not sure if your symptoms fit a OVP relay fault since it usually results in erratic engine complete cut out/ poor restart ???

 

[Iain]

Thanks Graeme.
I'm going to check out the voltage either side of the fuse on the relay.

 

[Iain]

Graeme.
Just looked for the OVP relay in fuse compartment. Nothing that matches the description with the fuse on top. Also removed cover from the box adjacent to bulkhead next to fuse box. Nothing resebling an OVP relay. Do you have any pics/links please?
Iain

 

[grober]

inner wing

Sorry don't have this model myself. Can be mounted on inner wing on some cars see http://www.detali.ru/cat/oem_mb2.as...417717.418&CT=F&cat=45H&SID=54&SGR=045&SGN=05
quote from another post " Just been informed by my local dealership that late model 202's don't have OVP relays. Apparently cars with the stubby plastic infra-red keys were not fitted with them."
so may not exist on your car at all. symptoms dont really fit either. might be a fuel supply problem? when was the fuel filter changed last?

 

[Iain]

Short, stubby is the answer. And the key!
I'll check the filter next. It's a salvage car with the bumper pulled off,so don't know when it was last serviced yet. Have already changed plugs for new and substituted coil packs for known good un's. Will keep looking.
Thanks

 

[big x]

You don't have an OVP relay,it was dropped when the electronic 5 speed boxes and updated fuel injection came in the 1997 model year.

adam

 

[Iain]

Thanks Adam. Graeme also found that out.
I've just bought a genuine MB maf off ebay for £62. If that doesn't work then at least its a spare to have. ( I also have a 'T' reg salvage car that has similar but not as bad running problems that might need it)Weather permitting, I will check the fuel filter tomorrow and post back with my findings.
Thanks gents for your input.

 

[Iain]

MAF finally turned up.
Car is like brand new again. Thanks again for all of those that posted.