ASR Light On

[stwat]

A mate of mine has recently bought a 1997 W202 230K. He gave the car a service, oil plugs, filters etc and also changed the diff oil. He was unsure what oil to use in the diff so says he got the info on the correct oil "off a merc site". God knows which site unfortunately. It's now a few weeks since he changed the diff oil and the ASR light has come on permanently.

The one thing he mentioned to me was that the old oil looked like ATF, ie, red. Whilst the new oil he put in was more like the usual hypoid diff oil.

Has he used the wrong oil? Is this the cause for the ASR light to be on all the time?

What is the correct diff oil for the car in question?

I haven't got a clue about the ASR system, is it connected to the diff at all? Or does it simply use the ABS system to apply the rear brakes a little when traction is lost?

The ASD system in my car uses a combined ABS/ASD sensor in the diff. I know this is a totally different system to the ASR traction control but does the ASR also use a sensor in the diff to sense when traction is being lost?

Thanks
Stu

 

[Will]

It's probably the brake light switch.

Having changed the diff oil could be a red herring.

Needs to have the fault codes read ideally, but a new brake light switch is a very common fault and cheap/easy to replace.

Will

 

[lynall]

Cant see it having anything to do with the oil, pretty certain the sensors are mounted wheel ends of the driveshaft, well they are on my car.

As Will says google mb brake switch loads of info genuine switch only £10.

Any decent 75/80/90 diff oil will do the trick as they are just a standard open diff.



Lynall

 

[grober]

This from Wikipedia on the W202??? Mercedes-Benz C-Class - Wikipedia, the free encyclopedia
Safety

The W202 confirms the typical attention of the brand to active and passive safety. At the launch the C-Class had standard driver airbag, ABS and integrated side-impact protection; the front passenger airbag became standard from 1995 onwards, and from the same period Traction control (ETS in the 4-cylinder models, combined with limited slip differential (ASD) or ASR in the 6 cylinders models) was available as extra cost. In 1997 ASR became standard in the C 280s equipped with the automatic transmission and in the C 36 AMG, as ETS in the 4-cylinder models, except for the C 180 and the C 220 Diesel.

With the 1997 restyling ASR became standard in all the models, except in the C 180 and C 220 Diesel. This last model continued to offer ETS available as extra cost. Moreover front side airbags and Brake assist (BAS) came in the list of standard safety features. The two basic models finally joined ASR in 1998, and, in 1999, the W202 was the first mid-size sedan to offer ESP as standard in all the range.


This is a bit garbled but seems to imply on the 4 cylinder models ASR systems were essentially an ASD/LSD type system. If this is the case its quite possible your friends diff contained hydraulic fluid rather than hypoid gear oil. This could be the cause ( possibly very expensive) of his problem.

p.s. since your friends car is one of the first Kompressor engined cars ---manual gearbox??? my bet is that it has ASD?? If it is there should be some form of hydraulic line/s to the diff housing. If you put his VIN number into here http://old.mbclub.ru/mb/vin/view.html?lng=eng it should tell you.

 

[Will]

I'd be surprised if his W202 had a limited-slip ASD diff, would be pretty unusual and the first W202 with an LSD I've ever heard/seen!

Being a '97 isn't it a fairly well established 230 Kompressor model, I think they came in around '95. Might it even be a facelift model with the traction control?

Will

 

[grober]

True you may be right Will. I am just guessing that because it is a 230K it will have come with some form of traction control as standard i.e. differential controlled ASD [code 212?] as opposed to brake controlled ASR.[code 471/2??] Vin number should confirm things. Lets hope for the poster's friends sake its something as simple as a brake light switch or ABS sensor.

 

[stwat]

Many thanks for the replies and info

The car definitely has ASR which was working perfectly fine the last time i drove the car. In fact it was annoying so i switched it off.!

I have a multimeter so il test the brake light switch. Or is it simply a case of seeing if the brake lights work?

Thanks,
Stu

 

[jaymanek]

Im not sure where the speed sensor on the rear is on that car but on many it is on the diff.. may just have knoked the wire?

 

[lynall]

Brake light usually has 2 switchs inside one for brake lights other for traction cruise etc.



Lynall