possible bad connection points for ESP Module?

[Wyersmith]

Hi, I'm looking for some advice on where the best places to look for poor earth/connectivity to the ESP module might be.

I've had a recurring but unpredictable fault on my 2000 W208 for about 2 weeks. When driving, ESP warning comes up, speedo and milometer fails, and locks in whatever gear it was in when fault threw. Stop and restart and the fault clears but reoccurs whenever it fancies. could be 20 miles, could be 20meters.

Faults started after having exhaust welded and front suspension looked at for knocking. front wheel speed sensor changed and all wheel speed sensors checked and working on a ramp with STAR.

Star brings up following codes:

Electronic Selector Module
P1876 - Signals sent by control unit N47 for the wheel speeds and braking torque are not available on the CAN bus. (current and stored)

ESP
C-1000-016 - Check control Unit N47-5 (ESP and BAS control Module) Check Power supply of component N47-5 (stored)

Vacuum Pump Brake Booster
C1025 - No or incorrect CAN message from control Unit N47-5 (stored)

ICM - Instrument Cluster
B1101 - Fault in CAN communication with control Unit N47-5 (stored_
B1110 - Communication through the interior CAN bus is faulty (current and stored)

From codes MB indy chap thinks it's more likely a CAN bus problem (shorted wire etc) than a faulty N47 and suggests a few hours chasing bad wires before going for a new ESP module (sounds pricey to me!)

The indy chap who does my other car and has been excellent thinks its more likely power to the N47 or bad earth somewhere. He thinks this could be creating the CAN bus problems.

so, any help on where the best places to check for a bad connection/earth would be much appreciated. I will also pull the relay and see what that's doing (is it ok to manually close relay to see if this takes ESP warning light out?). also, is it possible to test the circuits into the N47 (ESP) with the 'scart' connector using a multimeter? and would that help at all?

any suggestions would be much appreciated as this is annoying the hell out of me and as you can tell, I'm not much of a mechanic...

Thanks in advance

Wyersmith

 

[television]

This should be a broken wire on a front wheel ABS sensor to give all those faults, could be dirty damaged sensor

 

[Wyersmith]

ABS

Hi, thanks for getting back on this.

I missed a code in my previous message...

BAS
C1025-008 - CAN bus: CAN message ABS is faulty. (current and stored)

Interesting that you picked up possible ABS fault even though I didn't put it in first post. I hadn't considered that as although the ABS light comes on and stays on (along with the Brakes and ESP/BAS warning lights too) when it throws the fault, I don't get the ABS fault up on the central display, just the 2 malfunctions - ESP Visit Workshop and Display Defective ESP Visit workshop.
would a broken ABS sensor not trigger the ABS malfunction screen?

Thanks again. I will try to get a look at the ABS sensors.

Wyersmith

 

[Wyersmith]

not the wheel sensor

So, the wheel sensor has been replaced, the toothed wheel has been cleaned (as best as possible) and it all checks out fine on an ohm meter.

Took it out for a drive and it is still playing up as before.

My next thought is the ESP module although another mechanic has suggested it could be a bad earth. I can't see an earth connected to the ESP/BAS unit and replaced the nearest corroded earth anyway. also pulled and checked the relay. it looked fine. all very clean and shiny and no sign of heat. is the earth for the ESP/BAS unit within the multipoint connector?

On the next drive it was fine for about 5 miles then threw the fault 4 times in 2 miles. each time I stopped, switched off, switched on, fault gone, drove off and the fault was back in a few hundred meters. however, this time it was just one malfunction on the display - ESP - Display Malfunction, the speedo stopped and all three brake/ESP/BAS/ABS warning lights came up as before.

Now, I'm thinking that if the front left wheel feeds the signal to the speedo then it's a either a problem with the sensor (that checked out fine) a problem between the sensor and the ESP module or the ESP module itself (or another earth???)

any suggestions very much appreciated.

Wyersmith

 

[television]

If the ABS lamp is on it is seldom anything to do with the ESP as ESP rides on top of BAS and this rides on top of the ABS.

Could this be the brake lamp switch, ??? not thinking well tonight.

 

[Wyersmith]

Hmmm

I have wondered that myself. I've had 2 new brake switches in the last 3 years but they have been pattern parts so perhaps I should treat myself to a merc one and see what happens.

I just couldn't convince myself that a faulty brake switch would cause the speedo to drop out and lock the gearbox in one gear, but if you think a faulty brake switch might cause that through the ESP I suppose it's not the most expensive experiment.

I know how to take out and replace but is there any special set up I need to do to it when it's in?

Thanks for your help.

Wyersmith

 

[television]

We do know that faulty brake lamp switches can kill off speed signals temporary within the BAS ECU, I am not 100% on this being a fix, but possible.

 

[Wyersmith]

Hi,

I just found this thread on google from a few years back.

http://forums.mercedesclub.org.uk/archive/index.php/t-73747.html

Sounds like exactly the same problem. Alex Crowe suggested a new ESP module which seemed to do the trick. He never came back to say it had failed anyway!

Would you rule ESP mod out completely?

Thanks

 

[television]

Hi,

I just found this thread on google from a few years back.

http://forums.mercedesclub.org.uk/archive/index.php/t-73747.html

Sounds like exactly the same problem. Alex Crowe suggested a new ESP module which seemed to do the trick. He never came back to say it had failed anyway!

Would you rule ESP mod out completely?

Thanks

Well anything can go short circuit, taking the speed signal with it, it can happen but not common.

 

[Wyersmith]

Ok. Thanks for your help. 2nd hand ESP on eBay is not much more than the cost of a brake switch. I could change both and it would still cost less than doing another STAR at a main dealer.

Thanks again

 

[television]

Ok. Thanks for your help. 2nd hand ESP on eBay is not much more than the cost of a brake switch. I could change both and it would still cost less than doing another STAR at a main dealer.

Thanks again

As long as you please let us know the outcome, thanks

 

[Wyersmith]

I will.

On a slightly different note in your experience are there any of those 38 to 16 pin Obd adaptors that have more than just 3 pins connected?

I broke a pin off of my cheap eBay one and at a chance of more than 12 to 1 against managed to break off one of the 3 pins that actually does anything!

Happy to buy a cheap one again but if there are better connected ones available it would be good to know.

Thanks

 

[television]

I only know and use STAR, sorry just cannot answer this.

 

[Wyersmith]

No problem. Thanks.

 

[WG M-B]

It does sound like the esp module to me.

 

[Wyersmith]

300 miles on...

Firstly, thanks for the help from members here. It was really useful.

So, having changed the brake switch (which didn't fix the fault) I took to Ebay to find a 2nd hand ESP module and ABS pump. Unfortunately the prices were a bit higher for the part number I needed than I first thought. On later models you can pick up the same part for about £40. For mine the going rate was about £175! (ouch). So, I contacted someone breaking a CLK 230 and they offered me the parts for £50 (result!).

The parts arrived, exact match on the serial numbers, switched the ESP module and after a bit of fun and games with a new ABS fault momentarily appearing I cleared the codes, reset the steering sensor doing the lock to lock procedure, and 300 miles later the fault appears to have been cured. No lights on the dash, no EML and the speedo works as it should.

Hoorah!

Thanks again for your help MBO members. Until next time...

Wyersmith

 

[Mark Hart]

Hi everyone,

Just joined as I’ve been reading this thread and a couple of others since I have this problem on my 2004 clk500.

Had the car over a year, done less than 2000 miles as it was a project, never had a problem with it. Then over Christmas whilst trying to remove the right rear brake calliper, thread stripped on the wheel carrier, someone over tightened it and coated it in thread locker, argh.
Anyway fast forward past 2 months of hell getting the wheel carrier off, snapping the wheel speed sensor mount and having to cut off a few suspension arms in the process, it’s all back together now, new sensor and arms fitted... drove it to work the next day, boom, esp faulty visit workshop, brake wear (made me laugh) visit workshop, display faulty visit workshop, no speedometer, locked tranny in whatever gear it had selected.
Switch car off and back on, everything went back to normal.

This happened randomly over the next few days until the day I was taking it to my friends garage and the “off on trick” didn’t fix it, tranny wouldn’t select a gear so it won’t budge on a main road. My friend brought his code reader... no abs module anywhere to be found, like it had vanished from the car.

Called the aa because I thought it was dead, engineer arrived, disconnected the electrical connector on the module, reconnected it, no problems, drove it 40 miles home no problem.
Drove it again the other day, same as above, disconnect trick worked this time to get me home so I started looking for help online, came across this thread and I’m so grateful people have had the same problem and switching the module out has worked.

I’ve just ordered a second hand abs pump and module off eBay for £21 ( a steal if it works). My only concern is the one on my car has part number: A2095453032, this concerns me because:
1) according to wis this part number is not for my vehicle, either a2095452832 or a2095453132 are the right parts (3132) being the latest unit. This probably means the module was changed in the past.
2) to get one of the part numbers above would be over £170 so I’ve gone with the £21 a2095452932 from a 270cdi. I’m hoping Mercedes Benz followed a logical numbering sequence from 28 through 31 and the numbers increment as software numbers for the program.

Anyway thanks again guys for the information I’m hoping I get the same outcome you guys did.

I’ll post back with the results once it’s fitted.

 

[Mark Hart]

Hi everyone,

Just joined as I’ve been reading this thread and a couple of others since I have this problem on my 2004 clk500.

Had the car over a year, done less than 2000 miles as it was a project, never had a problem with it. Then over Christmas whilst trying to remove the right rear brake calliper, thread stripped on the wheel carrier, someone over tightened it and coated it in thread locker, argh.
Anyway fast forward past 2 months of hell getting the wheel carrier off, snapping the wheel speed sensor mount and having to cut off a few suspension arms in the process, it’s all back together now, new sensor and arms fitted... drove it to work the next day, boom, esp faulty visit workshop, brake wear (made me laugh) visit workshop, display faulty visit workshop, no speedometer, locked tranny in whatever gear it had selected.
Switch car off and back on, everything went back to normal.

This happened randomly over the next few days until the day I was taking it to my friends garage and the “off on trick” didn’t fix it, tranny wouldn’t select a gear so it won’t budge on a main road. My friend brought his code reader... no abs module anywhere to be found, like it had vanished from the car.

Called the aa because I thought it was dead, engineer arrived, disconnected the electrical connector on the module, reconnected it, no problems, drove it 40 miles home no problem.
Drove it again the other day, same as above, disconnect trick worked this time to get me home so I started looking for help online, came across this thread and I’m so grateful people have had the same problem and switching the module out has worked.

I’ve just ordered a second hand abs pump and module off eBay for £21 ( a steal if it works). My only concern is the one on my car has part number: A2095453032, this concerns me because:
1) according to wis this part number is not for my vehicle, either a2095452832 or a2095453132 are the right parts (3132) being the latest unit. This probably means the module was changed in the past.
2) to get one of the part numbers above would be over £170 so I’ve gone with the £21 a2095452932 from a 270cdi. I’m hoping Mercedes Benz followed a logical numbering sequence from 28 through 31 and the numbers increment as software numbers for the program.

Anyway thanks again guys for the information I’m hoping I get the same outcome you guys did.

I’ll post back with the results once it’s fitted.

Hi guys,

Part arrived from eBay yesterday, going to fit it over the weekend, looks an easy job the module is held to the hydraulic unit (came as one item) with four e4 torxs screws.

Did some research into making sure modules are compatible, what I’ve found is the Mercedes part number (a2095452932) is generally just for model assignment of the vehicle. So according to wis the two parts for my clk500 should be a2095452832 and a2095453132, the part which I bought off eBay is from a clk270 cdi which is a2095452932, the part on the car is a2095453032.
The module itself is made by ate and is stamped with their coding on the front panel too, this I think is the more important information because the clk had a midlife face lift so I believe a2095452832 where fitted to the initial clk500 and then a2095453132 was fitted to the facelift in 2004.

Looking at just the ate markings there’s no difference between software and hardware versions between a2095452932 and a2095453032 so I’m hopeful this is going to work. Attached images with the highlighted numbers in case it helps someone else in future.

I’ll let you guys know over the weekend if it was a success

 

[EmilysDad]

.... .....

I’ll let you guys know over the weekend if it was a success

Good luck

(You'd be better starting your own thread rather than tag on to a years old thread )

 

[Mark Hart]

Good luck

(You'd be better starting your own thread rather than tag on to a years old thread )

Will do