# Error code 55C3 (VTG: AWD limp-home control activated. No DSC specified nominal torque)



## james78 (Apr 17, 2017)

Hi all,

What does the 0055C3 error code mean? In my case, I get "DBC failure" and "4x4 system and DSC failure" and this is the ONLY code ISTA+ reads. Surfing the web suggest that usually this error is accompanied by other errors but in my case, I have no other failure.

*More Details*
Within the last few weeks, I've got "DBC failure" and "4x4 system and DSC failure" with few dash warning lights on. In all cases, it happened when cruising normally. Using INPA I read the errors and this is what I got every time. NOTE: Errors cleared after each reading.

*1st time - a few weeks ago*
00E205 PDC: K-CAN-High wire fault
0055C3 VTG: AWD limp-home control activated. No DSC specified nominal torque.
005E63 DSC: Brake light switch permanently actuated

*2nd time - last week*
00E205 PDC: K-CAN-High wire fault
005E63 DSC: Brake light switch permanently actuated
0055C3 VTG: AWD limp-home control activated. No DSC specified nominal torque

*3rd time - yesterday*
0055C3 VTG: AWD limp-home control activated. No DSC specified nominal torque

Seems like the main error is 55C3 but I couldn't find what it truly means.

Any thoughts? Any help, advice, and guidance are appreciated.


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## Doug Huffman (Apr 25, 2015)

DSC commands TC actuator to variably engage the TC wet multi-plate clutch to provide more or less torque to the front propellor shaft and wheels. I believe VTG limp-home means that the actuator is not communicating properly with the VTG module.


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## james78 (Apr 17, 2017)

Thanks Doug. Now it's starting to make sense to me  Any idea how I can troubleshoot further? E.g. is it a wiring issue, loose connection, DSC control module failure, etc? I was planning to change TC fluid as well as front/rear diff fluids but for now, I hold on until resolving this issue. In case I touch wires/connectors for worse.


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## james78 (Apr 17, 2017)

Do you think it has anything to do with the other error from first 2 incidents? 5E63 DSC: Brake light switch permanently actuated
I'm also wondering whether this is a sign of bad servomotor actuator?


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## Doug Huffman (Apr 25, 2015)

I do not have access to ISTA. My free help gave no troubleshooting Test Plan for the error. BMW Fault Code Lookup - BMWFaultCodes

Unless you have been hacking around in the area it is not likely wiring or connectors. In any case it is not likely DSC. The brake switch might, just might, contribute but needs to be fixed in any case for just this sort of complication. Deferred maintenance can be a bugger.

Yes, the TC actuator is the first suspect for me, plus it is relatively cheap and easy. You need to know what its proper capabilities are.

There are eight wires at its connector, two supply DC to the motor, two for the classification resistor, leaves four to the 'black box'. I believe that there is a Hall Effect position-rotation counter in the actuator.


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## james78 (Apr 17, 2017)

~8 weeks before this happened I worked around that area to change tranny sleeves and fluid. Not bad idea to ensure the TC actuator connector is tight and in-place. That I can do in 5 mins. If error comes back then focus on the TC actutor itself.

Thanks Doug a lot for your help. It may sound like 2 mins of your time to type, but it's saving me hours of headache and travel to shops. It's priceless help.


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## james78 (Apr 17, 2017)

Today it happened again! This time two errors at the exact same mileage (143976km). And this time I got error details (Environment conditions) from ISTA+. I'm wondering if the brake light error is triggering the VTG.

*0055C3 VTG: AWD limp-home control activated. No DSC specified nominal torque.*









*005E63 DSC: Brake light switch permanently actuated







*


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## james78 (Apr 17, 2017)

*Next step*: I'm going to replace the brake switch. I will share the results here.

*A test: *The issue happened a few times since I started this thread. I realized before the message comes on dash cruise control doesn't engage anymore. Haven't read the code at that moment but this seems to be just before 4x4 lights come up. So last few times when I notice cruise control doesn't engage, I gently pull the brake pedal using my foot and then I'm able to use cruise control normally. So it seems like the root cause is the brake switch confusing the rest of the system, starting from cruise control and if left too long then 4x4 and the rest. I hope this is the root cause. Will know soon.


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## james78 (Apr 17, 2017)

*Fixed*. Turns out the old brake switch was too compressed. Didn't even need a new switch. Probably it was marginal to detect whether the brake pedal is pressed. Perhaps because I've been playing in that area when replacing my brake booster last year. So instead of replacing the switch I simply pulled the switch back and pressed the pedal to recalibrate the switch. No more nasty and confusing 4x4 etc error messages. I'm calling this one done. Such simple switch has snowballing effect on so many other components of the car.


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## mbaril010 (Jul 3, 2021)

james78 said:


> *Fixed*. Turns out the old brake switch was too compressed. Didn't even need a new switch. Probably it was marginal to detect whether the brake pedal is pressed. Perhaps because I've been playing in that area when replacing my brake booster last year. So instead of replacing the switch I simply pulled the switch back and pressed the pedal to recalibrate the switch. No more nasty and confusing 4x4 etc error messages. I'm calling this one done. Such simple switch has snowballing effect on so many other components of the car.


Hey James

I seems to have the same issue as you. Could you help with clarifying what you mean with the brake switch was too compressed ? 
I have VGT, ABS, AC, ECM and TCM error.


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## james78 (Apr 17, 2017)

mbaril010 said:


> Hey James
> 
> I seems to have the same issue as you. Could you help with clarifying what you mean with the brake switch was too compressed ?
> I have VGT, ABS, AC, ECM and TCM error.


I hope your issue is as simple as mine. The following photo (from pelicanparts) shows the brake switch. The inner plastic piece is adjustable - like a ratchet mechanism. Normally when installed brake pedal is pressed and the inner plastic piece is all way out. Then brake pedal is released which will push the plastic piece back until brake pedal is resting. This is how the brake switch is automatically adjusted. In my case for some resaon the inner piece was too far in therefore normal position of brake pedal had still some gaps with the plastic piece which confused the car.


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## TheGoodTheBadTheUgly (Aug 14, 2021)

Hey James, hope you are doing fine!

I come from E90 platform and I have a 2011 N55 335i xDrive. I have been having the 55C3 error but nothing about the brake pedal or nothing since the last time I have scanned the car with ISTA at least.

I will try to scan the module tomorrow to see if something else appears, but the issue has been coming on and off just like you.

I did have an iDrive message appearing when the issue occured today qnd maybe it might point towards something, but for now I qm pretty lost 

EDIT: 
I scanned with ISTA and got a new code for the steering angle sensor, but I have no clue how this can throw the VTG code...


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## Millseen (Nov 12, 2017)

Hi, I have dealt with this exact issue on my e70 4.8i. I Replaced the battery, DSC, VTG motor, VTG module and updated the software to the latest i-level and I was still getting the same faults for 55C3 VTG: AWD limp-home control activated. No DSC specified nominal torque. 
It was driving me crazy. Sometimes the fault would happen in the first minute of driving and sometimes you would get 10 minutes, but ultimately the faults would always return. 
I remembered my E39 525i transmission had a freak out one time, i thought the trans was failing but after speaking to a bmw tech, he advised me to change the ignition coils, that he had seen the issue before, the ignition coils would perish and crack resulting in poor grounding causing all sorts of electrical interference. The E39 had all the symptoms of a failing transmission, I was sceptical of buying six brand new genuine coils into the car but i purchased them anyway, put them in and to my amazement the E39 instantly drove perfectly again, the transmission was back to normal. Couldn't believe it. Back to the E70, I pulled out the eight coils and they were in poor condition, I replaced all 8 ignition coils with genuine BMW ones and cleaned up the grounding wires to the cylinder head with sand paper (there is two per bank) I have never seen that fault since, that was roughly 17 thousand kilometers ago. I hope this helps someone else.


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## Snoop 3232 (Sep 21, 2020)

Millseen said:


> Hi, I have dealt with this exact issue on my e70 4.8i. I Replaced the battery, DSC, VTG motor, VTG module and updated the software to the latest i-level and I was still getting the same faults for 55C3 VTG: AWD limp-home control activated. No DSC specified nominal torque.
> It was driving me crazy. Sometimes the fault would happen in the first minute of driving and sometimes you would get 10 minutes, but ultimately the faults would always return.
> I remembered my E39 525i transmission had a freak out one time, i thought the trans was failing but after speaking to a bmw tech, he advised me to change the ignition coils, that he had seen the issue before, the ignition coils would perish and crack resulting in poor grounding causing all sorts of electrical interference. The E39 had all the symptoms of a failing transmission, I was sceptical of buying six brand new genuine coils into the car but i purchased them anyway, put them in and to my amazement the E39 instantly drove perfectly again, the transmission was back to normal. Couldn't believe it. Back to the E70, I pulled out the eight coils and they were in poor condition, I replaced all 8 ignition coils with genuine BMW ones and cleaned up the grounding wires to the cylinder head with sand paper (there is two per bank) I have never seen that fault since, that was roughly 17 thousand kilometers ago. I hope this helps someone else.


Did you ever figure out what it was


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