ABS Module - ESP, ABS and display faulty no speedometer

Mark Hart

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Your Mercedes
Mercedes-Benz C209 CLK500
Hi all,

First forum post!

I’ve got a C209 clk500 and I recently received the fault messages in the title. I replied to an old forum thread on here and was asked to repost as a new thread, here’s a link to the other post that contains all the background.

https://forums.mercedesclub.org.uk/...on-points-for-esp-module.142198/#post-1708845

So from the research I have done and from what other users have post it sounds like my abs module is slowly dying a tragic death.
A new one will set you back £1500+ at the dealer but I’ve managed to find an array of used parts on eBay ranging from £21 to £70.

My part arrived from eBay yesterday, I’m 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.

I’ve done some research into making sure abs modules from other cars are compatible with mine, 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 (supersedes the previous). The part which I bought off eBay is from a clk270 cdi which is a2095452932, the part on the car that’s failing 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. Essentially if you’re replacing this with second hand ensure the HW (hardware) number matches and the SW (software) number is the same or higher than the one on the car

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

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OP
Mark Hart

Mark Hart

Active Member
Joined
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Messages
25
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Location
North East England
Your Mercedes
Mercedes-Benz C209 CLK500
  • Thread Starter
  • Thread starter
  • #2
Hi all,

First forum post!

I’ve got a C209 clk500 and I recently received the fault messages in the title. I replied to an old forum thread on here and was asked to repost as a new thread, here’s a link to the other post that contains all the background.

https://forums.mercedesclub.org.uk/...on-points-for-esp-module.142198/#post-1708845

So from the research I have done and from what other users have post it sounds like my abs module is slowly dying a tragic death.
A new one will set you back £1500+ at the dealer but I’ve managed to find an array of used parts on eBay ranging from £21 to £70.

My part arrived from eBay yesterday, I’m 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.

I’ve done some research into making sure abs modules from other cars are compatible with mine, 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 (supersedes the previous). The part which I bought off eBay is from a clk270 cdi which is a2095452932, the part on the car that’s failing 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. Essentially if you’re replacing this with second hand ensure the HW (hardware) number matches and the SW (software) number is the same or higher than the one on the car

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

Hi guys,

Had a go at this tonight as I had a spare hour, as seems to be the theme with this car a 3 minute job quickly turns into a 3 day job.

Three E5 torx bolts which hold the module to the hydraulic unit, all three came off the spare no problem, top two came off the one on the car with a bit of force and a loud click, bottom one won’t budge, it’s on there so tight with a combination of over torquing and rust that the bolt head is stripped. Being a External torx 5 bolt it’s very small and unlikely any bolt remover can get it, going to have to drill it out and make sure I don’t damage the hydraulic unit in the process.

Some advice to you guys when changing these on your cars, wd40 is your friend, when you fit the replacement bolts it’s going into alloy on the hydraulic unit, the bolt is tiny, it doesn’t need to be more than hand tight with an e torx 5 socket attachment on a hand driver.

The design in the placement of this unit is poor on Mercedes part, the bolts are facing the radiator so are just going to get blasted with road spray coming through the grille, over the years so they will corrode quickly.
When I get my new unit fitted and the new bolts in, I’m going to coat the heads in multi-purpose grease and cover the bolt recess with some tape to try and prevent any corrosion should I need to repeat this job again.

More updates to follow...
 
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Mark Hart

Mark Hart

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  • Thread starter
  • #3
Ok so managed to swap over the abs module today.

The bottom bolt was fighting me because there’s a metal sleeve that runs through the module to support the bolt when it threads into the hydraulic unit, so much moisture had got in there the bolt had fused with the sleeve and took a considerable amount of force to break to lose.
Attached a picture of the problem bolt.
Cleaned the threads on the hydraulic unit using the three new bolts with a coating of copper grease, screwed in and connected first time, car started, no abs warning (good sign - the module was compatible), went for a 30 mile trip of mixed driving, no problems.
Before I declare it fixed I’m going to drive it over the next couple of days to be sure.

One thing I did notice was on the hydraulic unit where the electrodes slot into the back of the module, some had a blueish hue on the bases, I remember reading somewhere before that’s an indication of shorts and would support the theory about the old module being on the way out.

Thanks again for all the help from the forum, if it doesn’t go pear shaped I’ll be a happy mercedes owner again!

... next job, suspension overhaul, wish me luck.
 

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LostKiwi

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'93 500SL-32, '01 W210 Estate E240, 02 R230 SL500 (Malcolm Spec), 04 Smart Roadster Coupe
Blueish deposits on electrics agree usually a sign of water ingress (unless it's steel where it's a sign of high heat).
 

Blobcat

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Blueish deposits on electrics agree usually a sign of water ingress (unless it's steel where it's a sign of high heat).
As above, blue equates to corrosion on the copper.
 

Botus

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its rare on Mercs to see them play up.... but it 100% normal on all other brands.

I see you split the two not impacting the hydraulics… that's the failure mode fix on early ABS units - pre esp.... were a link wire between the multiplug and the circuit board falls off... and or rots "due to the accidental contamination during manufacture" that leaves a bit of poo on one wire till it corrodes to time !!!

the ESP / TC "wiper" motor not running due to gummed up brushes is the later preferred, designed in failure mode and its std on any BMW or virtually any other car.

Its remarkable you seldom see it come up on this forum.

both designed in faults can be removed guaranteed for life for 200 to 300 quid - if you fix yours then there's no agro with part numbers or engine / model specific coding for TC / ESP programming

https://www.ecutesting.com/product-catalogue/mercedes/cls/abs-pump-ecumodule-combined/amc960349/
 
Last edited:
OP
Mark Hart

Mark Hart

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Joined
Apr 26, 2019
Messages
25
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Location
North East England
Your Mercedes
Mercedes-Benz C209 CLK500
  • Thread Starter
  • Thread starter
  • #7
its rare on Mercs to see them play up.... but it 100% normal on all other brands.

I see you split the two not impacting the hydraulics… that's the failure mode fix on early ABS units - pre esp.... were a link wire between the multiplug and the circuit board falls of... and or rots due to the accidental contamination during manufacture that lease a bit of poo on one wire till is corrodes it to time !!!

the wiper motor still on the car is the later preferred designed in failure mode and it std on any BMW or virtually any other car

both designed in faults can be removed guaranteed for life for 200 to 300 quid - if you fix yours then there's no agro with part numbers or engine specific coding for TC / ESP programming

https://www.ecutesting.com/product-catalogue/mercedes/cls/abs-pump-ecumodule-combined/amc960349/

Thanks Botus I’ll keep that in mind if this ever happens to me again. One thing I didn’t mention was I was a bit of a plank when it happened to me the first time, I accidentally slammed the bonnet on the plastic cover for the wiring harness after removing and forgetting about it, smashing it to pieces.
Can I find just that cover on eBay for love nor money, however I did find another abs unit with the wiring harness and cover attached for another £20.
So in summary I’ve got a spare working abs module, 2 spare hydraulic units and a new cover hopefully that should see me over for the next 5 years.
 
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Mark Hart

Mark Hart

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Joined
Apr 26, 2019
Messages
25
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Location
North East England
Your Mercedes
Mercedes-Benz C209 CLK500
  • Thread Starter
  • Thread starter
  • #9
Hi guys,

Took the car on another 40 mile missed journey today, no esp or abs problems at all.

Thank you mercedes owners for your help, I think we’ve solved the problem!

For those just looking for the solution:

Replace esp module with a new unit, in my case a second hand unit off eBay that had a compatible hardware and software version for my car.
 

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