C180 Starting problems - HELP!!!!!!

[benz over]

I have an early 1994 w202 C180 that refuses to start. The car was running fine until it just refused to start - the key turns but the car will not turnover, not even a click. I have checked the battery which was ok. The RAC man managed to start the car by by passing the the starting circuit so that I could drive home. I also noticed that the central locking has stopped working - is this significant ??? I have been told that the problem maybe the starter lockout relay (K38). I have looked high and low and cannot find this relay - I dont even know if my version has one. I have a scorpion alarm system mounted under the rear seat which has been disabled for 2 years using the switch in the glove box so I do not think that this is the issue. Can anyone give me advice on what the problem maybe???

 

[Dieselman]

Check the fuses for the front SAM.

http://www.mbclub.co.uk/forums/showthread.php?t=62253&highlight=fuse

 

[benz over]

Have gone over all fuses and all seem ok - RAC guy also checked the fuses and the fuel pump relay when he helped recover me.

 

[benz over]

Does anyone know if early w202 c180's have a K38 relay and if so where it is?

 

[grober]

It sounds very like the aftermarket alarm system may finally given up the ghost. It usually disables the engine ECU via the OVP RELAY or FUEL PUMP RELAY or THE STARTER SOLENOID or a combination of these. Since its an aftermarket fitment the installations vary from car to car. However most alarm units are alarmed/disarmed via the central locking system. Despite the fact the alarm sounding/detection has been disabled its immobiliser features may still be operative. My guess is that your remote locking has failed in some way- the receiver units/LEDS or the convenience module below the rear seat or some wiring somewhere. This means the the alarm immobiliser is active preventing the car from starting VIA in your case only the starter solenoid. If you sort the remote locking the immobiliser will probably disarm OK but to prevent further problems take the car to a competant auto electrician who will remove/ short out the starter cut out relay plus wiring.

 

[benz over]

Thanks for this. I think the alarm was original equipment and was the same system used on the late 190's. The system went faulty about two years ago and I was told it was not fixable as scorpion had gone out of business so I disengaged it using the special key that inserts into the back of the glove box. The car has worked fine since, with no remote locking. The battery went flat about 3 months ago and as a result the immobiliser was reset and the car would not start I disengaged the immobiliser in the same way and the car was fine until now. I had heard that there is something called a starter lock out relay that controls the vacuum system and therefore the central locking, it also breaks the starter circuit. I wanted to to find out if this could be the problem but dont know where it is of how to find it. It is not listed in the Haynes manual. I thought it might be the same relay that locks out the transmission on P and N but cant be sure. As this is a big job and involves dropping the engine and gearbox to access it I want to be sure its nothing else first. Anybody had a similar problem with a pre DAS C180..?

 

[grober]

It could be that relay associated with the gear selector switch to stop the car starting unless its in neutral or park. ln later models the relay k38 was located in the relay box behind the main fuse box under the bonnet. I found another post saying that in some w202's it was located on the inner bulkhead behind the radio. Its attached via spade connectors which can give trouble.

 

[benz over]

I have stripped out the centre console and the carpets and trim from the footwells but cant find any K38 relay. Does anyone know what the K38 looks like or is it just a workshop myth - from all the threads I have read it appears I have more chance of seeing the Loch Ness monster!!!!!

 

[Dec]

Someone might be able to comment on this lot, I know 2 is the wiper relay, the other I don’t know about.
Same car and year as yours Benz.

Dec

 

[benz over]

Have you done much work to your benz? These early ones seem to be slightly different, particularly in the electrics department and the manuals do not seem to cover them in enough detail.

I have read much of what can be found on other MB forums, including the international ones - this problem seems to crop up frequently across all ranges but most commonly the W202's - I think it would be a great benefit if a conclusive diagnostic process and solution could be outlined for all to benefit...please comment if you can shed light on this. BO

 

[Dec]

Regarding this problem, I have had a trouble free existence, so far. My understanding of the security on my car, an Elegance, is that I have a Red and a Green LED on the rear view mirror and the drivers door handle.

When I unlock, via the flip out one button key, the vacuum pump can be heard running, all doors open and the green LED flashes for a few seconds and the immobilize is disarmed. No hazard lights flash.
When I lock, via the flip out one button key, the vacuum pump can be heard running, the Red LED flashes for a few seconds and the immobilize is armed. No hazard lights flash.

If the immobilize isn’t disarmed, the Red and Green LEDs will flash alternate when the key is turned to position 2 and the car won’t start just as you describe in your first post… “not even a click“… As grober has mentioned, your central locking being faulty could be linked to your starting problem.

The above, is all the security that these 1994ish car had when the arrived at the dealers, however, additional security was fitted by most of the dealers in the form of a Scorpion alarm which came with its own 2 button fobs and a round key to turn off the alarm, as in your case, in the glove box.

On mine, the only functions that the Scorpion alarm fob carry out is to alarm the car, lock or unlock (hazard lights flash twice) the car via the central locking system, the flip out key immobilizer isn’t involved with the alarm and the alarm has no immobilizer which seems to be the case with yours too, so I can lock with either or both key fobs but I can only immobilize with the flip out key. Bear in mind, all these alarms can be wired in different ways, the set up in my car may be different to your car, it all depends on how the fitter wired it all up.

I think, as grober, that your problem is linked with the central locking.
There is a Comfort control unit in the boot, hidden down the side of the battery, held by two plastic nuts, one each end.
The vacuum pump is located behind trim on right, inside wing of boot in a foam box, it would be worth checking the wiring on these two items.
Also check the two 3v batteries in the flip our key fob.
Test the key fob
In the front fuse box, take a close look at fuse 27 and maybe 28 and 23
In the boot fuse box (to rear of battery) take a look at fuse 3
I don’t know if your set up will be the same as mine but these fuses refer to the infrared remote control, the flip out key works on infrared.

Comfort control unit.
Test the key fob.
Keys.
Fuses.

Dec

 

[benz over]

Thanks for this Dec - My w202 elegance is one of the first and does not have the flip out key and the red and green lights. I have checked the comfort unit in the boot - all of the circuits and relays seem clean and in good order. All fuses are in good order. I have abandoned my remote controls ages ago as they both packed up hence having to switch off the alarm system, also my system is radio not infrared. Sounds like they used the end of the 190 parts bin on mine. I have not checked the vacuum pump yet so will go and do that know. I am still convinced this is a relay issue - but its not one that is under the front or rear fuse boxes so must be hidden somewhere else.

If anyone has found the starter lock out relay (K38) relay in a very early w202 please let me know or at least can anyone tell me what it looks like...

 

[grober]

This is a pic of the k38 in the W124. ITS BEHIND THE INSTRUMENT CLUSTER! If you havn't tried pulling it on the w202 might be worth a quick look see.

 

[Dec]

Another place maybe worth a look is passenger foot well, hinge the carpet back from below the glove box, you will see a metal footrest secured by 3 plastic? Nuts, there may be a few electronic things in there.

Dec

 

[benz over]

Thanks for this - I will have a look behind the dash. Can you tell me where I can get this level of detail on my benz?

 

[grober]

You can access the official mercedes WIS workshop information system here for a fee, but I think they insist on a vat number [ which they don't check] other folks have used a similar one in the USA but if you car wasn't imported there its of no use. http://www.service-and-parts.net/dcagportal/DCAGPortal/portal.action
Alternative is a DVD of previous WIS systems ( they will include your model since all models are covered) which crop up for sale on EBAY. This is an illegal copy of course so its up to you???? To view just type in mercedes WIS in the search box. It's not quite as simple as this since some computer/ operating system tweaks are sometimes required to get it to work properly as its mainly designed to work on a dedicated computer on a network?