When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I noticed that the buttons at the steering wheel only function when the engine runs. If the engine is off, the buttons behave erratic.
I first pulled the clockspring and measured it, but it is working. Found a document that describes the function of the buttons it says that the way the buttons work is like an resistor array, so the voltage defines which button is pressed.
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Could be cold solder joints.
Mine quit working and I found somewhere on the web
how to fix it, resolder cold solder joints.
Sorry, I don't know where now.
Be sure your battery is good.
I have seen they sell a steering wheel wire harness for rebuild, that could be a hint. Battery is a good point, I have 12.4V at the battery and to test it, I connected the battery with a charger, but no change.
Positive voltage is coming from the SAM and negative from a connector in the right footwell. I think I will pull the steering wheel again and measure the resistance of the cables. A better way would be to measure the voltage, no idea to get access to the connector with steering wheel in place. .
I measured the stand-by current, it is below 20 mA (connect multimeter instead of the negative cable from the battery, max.amp was 0.5A falling down to 16 mA after 30 minutes), Battery is ok.
I think I will buy a used clockspring,
Before just throwing random parts at the car, personally I would remove the steering wheel button assemblies and reflow all the solder. Costs nothing to try this first.
90 VW Corrado g60, 07 New Beetle Vert triple white & 09 Escalade ESV Plat LOL!
2x on previous post. Glad it functions when vehicle is running.
Just saw an unrelated post on a 2010 GM went through a similar issue. He replaced the clock spring twice with a generic version. Both were a No go. Third time was a charm with an OEM part.
The issue was no horn. There were no codes. He figured the generic part had a different pin out for his model. Don’t be like him, Get a MBZ or OEM part if you do end up replacing the clock spring. It’s a job you only want to do once and not guess if your No name part is no good.
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Were you able to clear SRS
after pulling the steering
Wheel? If so what scan tool
did you use?
I swapped mine recently, same wheel, from picknpull, just refinished. iCarsoft will not clear SRS for this vehicle.
Last edited by C230 Sport Coup; Aug 15, 2024 at 08:20 AM.
Sorry for late respond, took some time for trouble shooting, but now I'm quite confident that I found the error.
All buttons and the horn are connected with only 2 wires. The pressed button is detected by the resulting voltage drop when you press one button. Everything worked fine with engine running so it must have something to do with the voltage regulation or wire resistance itself. But where is the problem? So I tried to find the module where the cable ends and it is the EZS, the starter key module for cars up to 2004 (the old style multifunction wiper switch).
I removed the module, which is a giant pita to lie on you back with the pedals in your neck. Then you can shoehorn the module out. After removing I could measure the 2 cables through the clockspring and there were fine - sh...
So it must be the module. I installed the airbag again and the EZS module to do some more testing and noticed that the buttons worked when the ignition was on for 10 minutes or so, it was therefore temperature dependent not only voltage alone.
I opened the module and could identify a voltage regulator with not good looking solder points. I re- soldered it and...nothing.... but when I heat up this.chip everything works until it was cool again. The voltage regulator is broken, unfortunately only to get in China. I will order it and fix the module (fingers X).
I found several YT videos with repair of the EZS key module, if you have errors, there is nothing to lose.
.
BTW: If you disconnect the battery before removing the airbag you get no SRS error code.
90 VW Corrado g60, 07 New Beetle Vert triple white & 09 Escalade ESV Plat LOL!
Methodical, good step by step process into the diagnostics. The GM vehicle I was referring to was a Cadillac forum members 2010 Escalade. He avoided the SRS lamp from coming on by disconnecting the battery too.
BTW MBZ warns that disconnecting the negative battery cable only can waste the programing in modules and cause “significant additional reprogramming time” to the technicians job.
K
Originally Posted by gmzc320
you just have to be very sure to disconnect the battery, and disconnect the ground cable first and connected last, put your key on the starter in position 0 and everything should work fine… like in the manual says.
A new clockspring or start digging into the SAM (fuse box) is where things are pointing. It’s a good time to load test the battery and potentially replace the battery cables. I’m Noob to MBZ. My last one was in 82 with a 76 240D 5SP M, LOL. I got into air cooled with very early Beetles and a grey market 914-6 running triple Webers on a 2.7.
Moved into water cooled to get a/c with an Orig owner VW Corrado g60 & allroad 6SP M. I’ve been school’g up on the MBZ tech as fast as I can. The allroad 2.7T will soon be replaced with a C class.
Yes you can damage the early SAM modules when you disconnect the battery. The firmware in the microprocessor used had a design fault when you disconnect the battery in a non-stand-by state it could happen that the processor was bricked. The easy solution is before removing the battery cable wait at least 4 minutes with not touching the car before disconnect the battery. That means, no door open/close, no hood, no trunk just wait. If you open or close anything the waiting time starts again. I open the hood, close all doors and wait 5-10 minutes, get a coffee or so and than disconnect the battery cable at the dome. . .
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Good find on the chip.
You don't just want to buy a used module?
Do you have the part number by chance?
And yes. I F'd up and swapped the wheel with battery connected. No one around here has SDS and I don't want to buy another scanner unless I'm certain it will work.
The chip is TLE4267GATMA1 from Infineon which has a low tolerance and low stand-by spec for automotive application.
Problem with the used module is that you must find a way to clone the old data otherwise car will not start because it is part of the immobilizer system. And, I don't have Star Diagnose (because of this ****ty Siemens ECU my pass trough SD doesn't work).
90 VW Corrado g60, 07 New Beetle Vert triple white & 09 Escalade ESV Plat LOL!
In 2010 my local VW dealer installed cameras above all the techs workstations. You’re right, the guy would probably have to take the module & equipment to the bathroom so nobody’d see him doing it.
I changed the voltage regulator on the board and everything worked again - Huraay Cannot believe that I found the problem and was able to repair it .......
It is the module where you put the key in. In later models there is also a module dedicated to the steering column alone.
Electronic Ignition System (?) Ignition is Zündung in German.
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
You're brave to mess with the EIS. There's apparently another chip in there
that contains the vehicle specific data that allows the car to start.
Good thing you got the right chip. Even more amazing you managed to track down that the chip
was even in the EIS and which chip it was. Did you already say how you did that? I'll have to go back and read again.
Mercedes doesn't exactly publish schematic for the Siemens modules. How DID you every track that down?
Thats some serious troubleshooting. You da man!
Last edited by C230 Sport Coup; Aug 29, 2024 at 02:57 AM.
Will it let you edit the title of the thread to add (Resolved)?
I don't know how.
It was luck that the error disappeared when the part warmed up. With the EIS/EZS you have not many options. You can go to Mercedes, 1000$+ ?, or buy a used and go to a company to copy the data, don't know how much it is.
You're brave to mess with the EIS. There's apparently another chip in there
that contains the vehicle specific data that allows the car to start.
Good thing you got the right chip. Even more amazing you managed to track down that the chip
was even in the EIS and which chip it was. Did you already say how you did that? I'll have to go back and read again.
Mercedes doesn't exactly publish schematic for the Siemens modules. How DID you every track that down?
Thats some serious troubleshooting. You da man!
Thanks!
First I identified and measured the cables, which was not so easy. To get the steering wheel off was a two man job. I first thought the clockspring was bad, so I measured it and all was fine. Then I tried to find out where this cables from the clockspring ended, which was also not so easy because they changed it when the round style blinker switch.was introduced. And, I noticed that the error was gone when the engine runs, so voltage above 13+ V. It still could be a broken cable, but if the steering wheel switches are identified by an resistor array (only 2 cables supply all switches), they must stabilize the voltage and it must be in the module.
So, I removed the module (no fun lying on your back with the paddles in you neck) and opened it. I could easy identify the 2 tracts from the steering wheel and they got straight into an unidentifiable processor - shoot.
Ok, but the error is voltage related, so, as a rule of thumb, MOSFETs, voltage regulators, parts with high demand of cooling are often a point of failure. These chips are easy to find just by looking around. A MOSFET you can measure with a multimeter, that was ok. I took the soldering iron to reflow some solder points, also at this voltage regulator and connected the EIS again to the car and it worked (?). Maybe the reflow did it? One hour later it didn't work again, so it must be heat related and it was clear that the voltage regulator was broken.
Next time I have a broken module (please no) I will open it and check this simple parts on the board first. If somebody wants to buy this part, try to find it from Infineon Automotive, they cost 3$ per piece, all lower prices are not for Automotive.application.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
Nuf said. Much WoW!
