What is going on?! Please Help!! :confused:

[MercMLman]

Good afternoon all,

Sorry to start my membership to this forum with a plea for help, but I am at a loss as to where to turn and the local garages answer is to just keep replacing parts at huge cost until maybe...the lights go out!

So here is the scenario...

I have a 2004 ML270CDI that has started to show up the following lights on the dash when I start the engine - BAS/ESP, ETS, ABS and then when you start to move the jeep, the EPC light comes on - the weird part is that this does not effect the car in anyway, no powerloss, the ABS still works (Ichecked on a quiet road) but the cruise control doesn't work!

However if you are rolling slowly and put the car in 'N' and turn it off and then on again still whiloe movng slowly and the put the car back in 'D' all the lights go out, the cruise control goes out and you can drive from London to Manchester without it coming back on again.
Also sometimes it comes on, you drive 1mile, turn the car off go into the shop and when you come back out and turn the car on - the lights aren't on!

The garage have run diagnostics and claim that the nearside ABS sensor is running 2-3mph quick than all of the others - which doesn't make sense as the sensors simply read ridges that rotate and sensors should either work or fail, shouldn't they?

Please help - I've no idea what to do and don't really wanna get into just replacing parts with the garage - incase they might work - but might not!!! :sad::!:

 

[bigbear]

You really need to get it hooked up to a STAR machine

 

[MercMLman]

Thanks for the reply, it's been on a diagnostics machine, but that wasn't conclusive - they did have a fault showing for the sensor - but when they examined the sensor it all seemed fine!
Will a STAR system show up anything more than a normal in depth diagnostic system at a garage?

Thanks,
R

 

[television]

I would have hoped that STAR would do a better job, it does all seem down to the Speed signal possibly sensor or SAM loosing contact with it

 

[alec2]

Have you checked your tyres. Are the pressures OK. Are they all at the same state of wear?

Alec

 

[MercMLman]

Hi & thanks for the reply,

yep all 4wheels are the same size, pressure and wear.

It's all very strange

 

[Alex Crow]

I suggest you check the ESP relay in the under bonnet fusebox - maybe swap it for another one in there of the same part number.

After that have a look at the wiring loom at the hydraulic unit, they can chafe on the chassis or plastic wheel arch liner.

 

[jefrs]

Electrical gremlins!

The BAS/ESP, ETS, ABS or in my case the BAS, ESP and ADS, Parametric Steering too, are all inter-related.

I still have not resolved mine intermittent failures but we think we have traced it to the black box containing the ADS and ESP units.

I have managed to improve the situation but not cure it yet.
Points to look for -
1) battery voltage. Very fussy. You can still turn the engine over with the battery below optimum.
2) earthing points. Brown wires bolted down showing signs of corrosion. Some are hidden, and faults can be weird, like wipers kick when xenons come on (fixed that).
3) dry joints. For some reason MB used lead-free solder instead of crimping. Lead-free corrodes and oxidises. Otoh I've only had one actual lead-free failure, the rest look bright and shiny.
4) broken or melted insulation. This has been confined to tiny wires in the door mirrors.

 

[MercMLman]

Hi and thank you for the responses - I will be checking the advised relays and wiring looms - however a quick question is;

1) The ABS sensor that showed up on diagnostics is supposed to be reading 2-3mph quicker than all of the others - I have removed the sensor, cleaned it and also the reluctor/sensor ring to remove any dirt which may through up a false reading.

However do you need to reset the sensor or would the car do it itself during a cycle on start up? in which case I haven't fixed it! lol

 

[Roxie]

If this sensor is reading faster than all the others. Does this mean that it shows 2 mph when stationary? If so either it or the wiring to it are faulty. If it is a front one the wiring can corrode/chafe in the inner wing.

 

[Alex Crow]

Are the tyres all the same sizes, do you have a flat tyre? That would do it!

 

[MercMLman]

If this sensor is reading faster than all the others. Does this mean that it shows 2 mph when stationary? If so either it or the wiring to it are faulty. If it is a front one the wiring can corrode/chafe in the inner wing.

Thanks, I would have to speak with the old garage and see if this is the case, I cannot get the car MOT tested as the ABS light is the problem and although the ABS works (I tested that on a quiet road).

We've cleaned all the sensor and the sensor ring but does the sensor fault need to be reset or will the car do it itself on a start up cycle?

Thanks for all your help people, very frustrating!!

 

[MercMLman]

Are the tyres all the same sizes, do you have a flat tyre? That would do it!

Yep, all tyres are same size, brand and pressure and not excessively worn :-(

 

[Kyliewww]

I have a code reader that may help. I see that you are not too far from me.

 

[MercMLman]

I have a code reader that may help. I see that you are not too far from me.

Thank you so much for the offer, I have read the codes using a code reader called an 'Autel Maxi Scan Ms509' but that isn't in depth enough (normal car scanner) - I think it needs a 'proper garage reader' if you know what I mean?!
Although if yours is a more indepth system I would of course be hugely greatful of the help, just don't want you to waste your time if it can be avoided

 

[Kyliewww]

Very similar to what you have but mine covers ABS and Airbags too. Never a waste of time if it helps.

 

[andy@pcd-ltd]

What is the actual fault code you are getting on the system

 

[MercMLman]

Very similar to what you have but mine covers ABS and Airbags too. Never a waste of time if it helps.

Perfect!
Then if you're free at some point, it would bre great to see if your's shows up anything new to mine!

What is the actual fault code you are getting on the system

Will have to look this evening as not got the info on me :-(

 

[Kyliewww]

Will send you a PM [Edit] I can't! Not enough posts!

 

[Kyliewww]

OK, can do tomorrow before 6:30pm... I have a meeting at 7pm, or Thursday this week. You can mail me using any details from www.dead-ringer.co.uk Might be easier!