W124 abs light on and hard to start

[dragster425]

Anyone have experience of a hard to start from cold w124? mines a 200te. The ABS Light is on and it stays on after starting. It will start but has to be cranked for a long time, once started it will start easier when its warm. I have changed the silver relay on the ABS pump with a second hand one with no change

 

[bolide]

Replace the fuse on top of the OVP relay. It is a big silver relay beside or behind the battery. There can be one or two fuses in the top under a cap

Nick Froome

 

[grober]

If its not the fuses themselves then it may pay to repair the OVP by resoldering the relay small internal circuit board-- they tend to develop dry joints over the years due to vibration. Any local TV repairman should be able to do this for you for about £10 if you don't feel up to doing it yourself.

 

[balge]

Also check the brush/diode pack in the alternator, this is exactly what my 230TE did last time the diode pack went
cheers

 

[dragster425]

How do I check the brush diode pack?

 

[dragster425]

Just to clarify, I changed the silver relay next to the black one thats under a plastic cover on the ABS. That is the one?

 

[grober]

Just to clarify, I changed the silver relay next to the black one thats under a plastic cover on the ABS. That is the one?

no The OVP next to the bulkhead behind the battery- IDENTIFY BY FUSES ON THE TOP.

 

[balge]

How do I check the brush diode pack?

Screwed to the back of the alternator, brushes may be worn, check the Voltage output with a meter, replace alternator regulator if out of spec - less than 13V or more than 14.5V iirc

cheers

 

[dragster425]

The fault is intermitant, would that still be the same diagnosis?

 

[dragster425]

found ovp, fuse ok. It doesnt always have the starting and abs light problem, could the ovp have an intermittent fault?

 

[stwat]

Yes. As Graeme mentions it could have a dry joint on the circuit board. It is a very common fault on Mercedes of this vintage.

 

[GP801]

The OVP relay is involved in all sorts of things including the fuel pump. As above they can be resolderd but a new one was around £80 for our 280.

 

[dragster425]

Seen a few on Ebay for around £25. can the board be tested?

 

[hotrodder]

They probably can be tested but as said the most common fault (other than fuses) is bad connections on the soldered joints. Instead of going over the thing with a magnifying glass just resolder all the joints and see if that fixes the problem. Or replace with a known good one. Fuses that look OK/aren't obviously blown can still be worth changing... the continental style used can 'go bad' with age- hairline cracks/corrosion etc resulting in poor contact

Again as said the OVP relay is involved in all sorts of things, another being supplying power to the ABS which has a threshold voltage- below this/if it's not happy with it's supply the warning light will be triggered

 

[Braincrank]

I had a similar problem some time ago. ABS light was on and off and engine wasn't running properly when the light was on. The fuse looked ok but inspecting it closely it had a very tiny gap and that's why the problem was intermittent I think. New fuse solved the problem immediately.

 

[griffo]

i have a 1995 c200 . abs light is on and speedo not working please help

 

[BlackC55]

That the codes read. I suspect a speed sensor is faulty. The one in the diff is quite likely.