W211 5 speed auto problems following conductor plate and speed sensor change.

[timon]

After changing the conductor plate, oil change and checking the relays, the gearbox works fine. But I had no cruise control, and both ABS and ESP messages and speedo malfunction. So my indy garage changed the speed sensors. All was well for 100 yds when the ABS and ESP etc messages returned. The diagnostics said it was the front offside hub, so we changed the bearing and the speed sensor as the hub plate itself looked OK.

The same thing happened - for 100 yds all is well, then the messages return. This time the Cruise control doesn't show at all on the dash - before it just showed the dotted line.
Could it be an invisible fault on the hub, a fuse, the ABS unit, or a wiring fault somewhere between dash and sensor? I'm at a bit of a loss where to look. Any help gratefully received.

 

[timon]

I think I'll go back to a W140. At least I understood that and it never let me down. A high mileage W211 is no fun and no one seems to want to help an old feller.

 

[LostKiwi]

More likely a case of no one knows.
However... I'm a firm believer in the principle that if something worked, you changed something and now doesn't work look at the thing you changed.

 

[Wighty]

It’s a shame you haven’t got a reliable garage down there .

 

[LostKiwi]

Where in SW France are you? I'm just north of Bordeaux at the moment (until tomorrow).

 

[Botus]

I "think" decent data received by the traction control unit, (linked with esp and cruise control) are all part of the gearbox electoplate programming

I bet playing with the wheel sensor is a red herring.... error comes on after 100m because that enough time of the car to process info re TC /ESP and say hang on, I'm receiving garbage somethings wrong throw the safety warning

electroplate programming is supposed to be online session with germany to push the correct software at it.... it can be done bodging with naughty tools but you need the right kit and a bit of experience.... and the right components inside the box

mix and match parts and mix match / missing software will get you the sort of issue you're seeing

 

[timon]

I "think" decent data received by the traction control unit, (linked with esp and cruise control) are all part of the gearbox electoplate programming

I bet playing with the wheel sensor is a red herring.... error comes on after 100m because that enough time of the car to process info re TC /ESP and say hang on, I'm receiving garbage somethings wrong throw the safety warning

electroplate programming is supposed to be online session with germany to push the correct software at it.... it can be done bodging with naughty tools but you need the right kit and a bit of experience.... and the right components inside the box

mix and match parts and mix match / missing software will get you the sort of issue you're seeing

 

[timon]

Thank you, you may well be right. So, back to the gearbox. Interestingly I remember reading of someone else who had this problem after 100 m ie. everything fine and then warnings come back. It changes gear correctly now, the speedo works, it's just the constant ESP/ABS and brake warnings and the Cruise that don't.

I bought my first Merc when I'd been in a (W123) taxi in Frankfurt that had 860000km on the clock. The driver said he hadn't changed the engine but would change the car at 1million. I was so impressed I bought one, then several 124's and matterly the W140 which someone wrote off for me last year, whilst fiddling with their telephone.

This W211 has "only" done 360000 and it never stops nagging me. How can the brakes need attention when the sensors and pads have all been changed. And they work fine.

More likely a case of no one knows.
However... I'm a firm believer in the principle that if something worked, you changed something and now doesn't work look at the thing you changed.

LostKiwi - your diagnosis about change is fine except that before changing the electoplate the car kept going into security mode and staying in second or giving the impression of a slipping clutch. At least now it's driveable. Sorry if I was grumpy earlier. Just frustrated.

 

[timon]

sounds like it it's either main dealer or a clifftop.

 

[Botus]

if its got SBC brakes there's a few thing to check.
Condition of the small battery under the bonnet hidden under the air intake / pollen filter
A recall early on for wiring loom and a damper/ silencer
And then the physical counter of how often they've been used.... built in warning after x number of operations....

 

[Botus]

the days of long term longevity on modern vehicles is dead

lots of miles inside 3 to 4 years no issue.... expecting anything made after 2007 to do 20 years at a sensible cost, isn't part of the manufacturers business model

 

[Wighty]

sounds like it it's either main dealer or a clifftop.

If you take the cliff top option , make sure you don’t have any loose clothing that will catch on the car as you step clear

 

[pgh13]

Thank you, you may well be right. So, back to the gearbox. Interestingly I remember reading of someone else who had this problem after 100 m ie. everything fine and then warnings come back. It changes gear correctly now, the speedo works, it's just the constant ESP/ABS and brake warnings and the Cruise that don't.

I bought my first Merc when I'd been in a (W123) taxi in Frankfurt that had 860000km on the clock. The driver said he hadn't changed the engine but would change the car at 1million. I was so impressed I bought one, then several 124's and matterly the W140 which someone wrote off for me last year, whilst fiddling with their telephone.

This W211 has "only" done 360000 and it never stops nagging me. How can the brakes need attention when the sensors and pads have all been changed. And they work fine.



LostKiwi - your diagnosis about change is fine except that before changing the electoplate the car kept going into security mode and staying in second or giving the impression of a slipping clutch. At least now it's driveable. Sorry if I was grumpy earlier. Just frustrated.

What are the chances that the new conductor plate is faulty? So, it fixed the original problem but maybe introduced this new problem..... Speed sensor, perhaps? Also, someone mentioned the new plate needs coding. Is that correct on a 5 speed?

 

[Botus]

What are the chances that the new conductor plate is faulty? So, it fixed the original problem but maybe introduced this new problem..... Speed sensor, perhaps? Also, someone mentioned the new plate needs coding. Is that correct on a 5 speed?

not sure on the 5 speed ones, but on the 7g I believe there is an early and later version both physically fit but the wrong one misbehaves