W208 CLK430 Cabriolet 2001

[2247bspl]

Came to start my wife's CLK430 today and all the lights to the left of the instrument cluster came on (BAS/ESP, brake warning, etc) as did the Central triangle warning light and the "engine" light. I could hear the fuel pump start but nothing further happens as the ingnition switch is moved to the final position to start the car. There is no noise from the starter motor and the headlights remain bright. The battery is less than six months old. Any ideas?

 

[type49]

Does the rev counter jump when you try cranking postion?? Try it ten times to see if it jumps at all...

 

[2247bspl]

W208 clk430

No. There is no movement of the Rev counter at all.

 

[television]

Do watch that rev counter when you turn the key to start, if it did not jump the you need to check the voltage on the small terminal on the starter motor when the key is turned

 

[2247bspl]

I am quite certain the rev counter does not flick at all however many times I try. I understand the need to check power to the starter solenoid but how can I gain access? There does not seem to be any room around the engine bay from above and I can't even see the starter!

 

[Alex Crow]

under the bonnet on the passenger side you have a black plastic housing with a lid secured with 4x screws. remove this lid, and look at the control module nearest the front with fuses on - do you see the large-ish diameter purple wire that connects to it? this goes direct to the starter motor, so test for voltage here and report back.

 

[2247bspl]

Thanks. Getting somewhere now. Initially, there was no voltage on the purple wire but when I tapped around the area (particularly the relay mounted near the fuses on the same board) the engine started fine. I'm looking into the relay and nearby wiring as the fault is still there.

 

[Alex Crow]

the relay is mounted in the k40 unit. there may be a dry joint inside the unit, or it could just be a relay fault - why not pop the cover off the relay and check/clean the contacts?

 

[2247bspl]

I have just done that but the problem didn't go away. The car only started as I dislodged the mounting box and turned it over. Maybe the fault is inside the mounting box (K40?) or one of the wires to it. Still looking.

 

[2247bspl]

Not having much success. The relay is not pulling in. If I manually make contact (with the relay lid off, force the contacts to close) the starter turns the engine over though the car wont' start under those conditions. At least the starter is not faulty! So the problem must be somewhere upstream of the relay I guess.

 

[2247bspl]

Mobile again! Not too sure for how long but after removing and reconnecting the "ABS-PC" box (K40?) the car starts every time. I have looked inside the box too but can't find a dry joint. As a precaution, I will change the relay but I'm not too sure that this was really at the heart of the problem. Anyhow, many thanks to you guys for the guidance and for narrowiing the problem down. It has been a real help.

Ian