W169 A-class ESP light comes on when brake pedal pressed

[swiftguy]

Hi,

Having a real torrid time with this car. We spent over £1k fixing the gearbox bearings and ECU. Now a year later the ESP light (and engine management light) comes on when you hit the brake pedal for the first time after engine start. It then goes into limp mode max speed 30mph.

MOT is due early march. One thing that might be relevant is the garage that reapired the gearbox left it out in the rain and we'd notice the spare wheel are had quite a bit of water in it, I'm guessing he left the rear hatch open, I don't if this has somehow caused a short in the electrics - this now a year later this problem as manifested.

From reading around, people are referring to a brake light switch. I've tried the steering wheel from left to right, this didn't work.

 

[streethawk]

Brake light switch is cheapest option but ideally needs plugging into a star diagnostic

 

[swiftguy]

Thanks, reading around it does seem to point to brake light switch as being the cheapest option - even cheaper than first getting a STAR diagnosis.

I'm just wondering whether I'm competent to do the job.

 

[streethawk]

Thanks, reading around it does seem to point to brake light switch as being the cheapest option - even cheaper than first getting a STAR diagnosis.

I'm just wondering whether I'm competent to do the job.

5 min job just get on your back in drivers footwell

 

[wongl]

Make sure you get an original part from Mercedes. Should only cost around £15 or thereabouts.

 

[swiftguy]

Yiiiiiiiippppppppppppeeeeeeeee!!!!!!:bannana:

Man, I've not felt this good in a long while.

This ESP problem has been plaguing us for the past couple of months, we've just been driving the car around in limp mode.

The problem first manifested itself after we took it for a service at a local garage who did all the service bits, oil, oil fiter, spark plugs, brake fluid etc. We thought he had done something as the ESP light appeared shortly after he had serviced the car. He spent quite some time on it trying to figure what the problem was. He made us get wheel alignment, new front tyre, he tried his computer, nothing worked.

I was getting really worried as MOT is due, the ESP light coming looks like a very serious problem along with it going into limp mode. Spending the weekend researching on the net, coming across the brake light switch problem.

Replaced it and it ESP light gone. The car drives normally again and goes over 30mph!!.

It was quite fiddly to do. I had to remove the plastic cover which is held by 2 torx screws - I didn't remove it completely just left it loose so could access the brake light switch, press tab, turn and remove. The faulty switch you could see the stopper was a lot shorter than the new one. It was quite difficult getting the new one in as it just wouldn't go in, eventually it went in and all was well.

I got the part from Mercedes £13.22 (I saw some on eurocarparts going for £7), I joked with the Mercedes parts guy, this must be the cheapest repair ever for a Merc. I asked about the STAR diagnosis - costs £50+VAT.

They had some very nice cars in the showroom - was drooling over the new GLC. £34k! that's a lot of money, maybe 3yrs down the line, I'll look at one, let some rich kid take out half the depreciation.

Anyway, this a-class, as soon as it gets MOT, it's getting part-ex or sold.
Need a reliable auto - will prob look at a Honda Jazz or Toyota Yaris as a replacement (CVT version not I-shift or MMT).

Thanks guys for the pointers and help.