Code C0034

Tiny
BILL PARRISH
  • MEMBER
  • 2012 MERCEDES BENZ C250
  • 1.7L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 50,000 MILES
Had multiple warning lights come on. EPS, ABS, EPS off, and engine light. Pull a C0034 code that indicated that right front speed sensor was bad. Replaced that sensor but I cannot clear the code in the vehicle. I can clear diagnostic codes but not pending codes, so the C0034 code is still there and the warning lights all remain lit. Additionally the "attention asst" is inoperable. Any ideas?
Monday, October 30th, 2017 AT 2:13 PM

15 Replies

Tiny
KHLOW2008
  • MECHANIC
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Did you check through all systems and clear all fault codes? Can-bus system is rather unforgiving and if any codes triggered are recorded in other systems, they need to be cleared.
Any possibility the replacement part is faulty?
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Monday, October 30th, 2017 AT 10:44 PM
Tiny
BILL PARRISH
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Sorry for delay in responding. I actually have TOAD Scan software that I got up and running to see if it could give me more info. See attached. Again I cant clear the codes even with the toad software vs scan tool. I have not checked to see if the replacement part is good. I was trying to find info on how to test the part but cannot. Can you provide any info on part testing? Thank you
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Friday, November 10th, 2017 AT 6:45 AM
Tiny
KHLOW2008
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For testing of wheel sensors, with a scan tool it should be easy. Go into live data display and monitor the various sensor speed while driving the vehicle around. If you have a hoist, with vehicle lifted or jacked up, manually turning the wheel would allow you to check if it is functioning. However this does not mean the sensor is bad if it is not reading. It just tells you the circuit has a fault and it could be the control unit, wiring or even the sensor pickup ring.

I don't have aceess to our database for the time being so I am not able to tell you the specifications for the sensor for testing. Hopefully I can get this resolved soon
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Saturday, November 11th, 2017 AT 6:40 AM
Tiny
BILL PARRISH
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I have the TOADscan software and this scan tool (https://www.harborfreight.com/can-obd-ii-scan-tool-with-abs-60794.html) but I cannot see how to or where to check the speed sensors. i took the car for a drive with each scan tool and tried to find how to check speed sensor. i can read systems but i don't see where i would be able to read a component or perhaps i don't know how to use the tools.

I suppose the new sensor could be bad but that would be pretty unusual. any ideas?
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Monday, November 13th, 2017 AT 12:38 PM
Tiny
KEN L
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IDK if you can get live data with that tool. Here is a video of a scanner that can get live data.

https://youtu.be/rTtAnsOlZU4

It does sounds like the wiring or ABS module is out. Here is an ABS wiring diagram and a guide to help you see what is going on.

https://www.2carpros.com/articles/how-to-check-wiring

Please let us know what you find. We are interested to see what it is.

Cheers, Ken
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Wednesday, November 15th, 2017 AT 6:33 PM
Tiny
BILL PARRISH
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Thank you for the info and drawings. I watched the video and located the scanner you suggest, however, it appears that this scanner will not work with Mercedes. Is that true? Is there another one I should consider?
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Wednesday, November 15th, 2017 AT 7:14 PM
Tiny
KEN L
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You might need to get a scanner that works with Mercedes Im not sure if the one in the video supports MB.
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Thursday, November 16th, 2017 AT 10:21 AM
Tiny
BILL PARRISH
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I recently go a iCarsoft scanner that works with Mercedes. I pulled the following codes from the ESP system C237100, C32600, and C111700 however the fault codes are not in the database of the scanner. Do you know or can find out what there are in relationship to?
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Friday, November 24th, 2017 AT 5:08 PM
Tiny
KEN L
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I think you can just leave off the 00 at the end of the code number C237100 would be C2371. Have you tried a hard reboot of the computer system? Remove the negative cable from the battery and hold it to the positive cable terminal for 20 minutes this will discharge the capacitors to reset the system protocol.

Please run this test and get back to us.

Cheers, Ken
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Friday, November 24th, 2017 AT 5:27 PM
Tiny
BILL PARRISH
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I did do a hard reset and then drove the car at various speeds, WOT, idle and it did not reset. Still have the same warning lights and DTC codes.

Are you able to determine what those three codes mean or is that something that only a dealer can do?
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Friday, November 24th, 2017 AT 5:51 PM
Tiny
KEN L
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It sounds like you have a communication error between one or more of the computers on the network. Did you check all of the fuses because just one fuse out will cause this problem.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Please let us know what you find. We are interested to see what it is.

Cheers, Ken
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Sunday, November 26th, 2017 AT 12:38 PM
Tiny
BILL PARRISH
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All the fuses are good. I have been able to find out, possibly, what some of the codes me. C3271 might be the ESP system, c3256 might be the right rear ABS. So with the c0034 right front speed sensor, its all over the car. This seems to suggest that it is a control module of some sort. Obviously if I could find that out it would be helpful, otherwise I am going to have to take the car somewhere.
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Wednesday, November 29th, 2017 AT 7:52 AM
Tiny
KEN L
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Did we ever check the wiring between the left front sensor and the control module? Here is a guide to help you just use the wiring diagrams above

https://www.2carpros.com/articles/how-to-check-wiring

Please let us know what happens.

Cheers, Ken
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Wednesday, November 29th, 2017 AT 11:15 AM
Tiny
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I will try that now, if I can figure how to get the cover off that thing ;-)

also I access to Mercedes WIS/ARSA if that is helpful. Trying to slug my way through it.
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Wednesday, November 29th, 2017 AT 1:07 PM
Tiny
KEN L
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Please let us know what you find. We are interested to see what it is.

Cheers, Ken
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Thursday, November 30th, 2017 AT 11:35 AM

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