No steering wheel comms Code C1200B
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Joined: Nov 2003
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From: Bowie, MD
No steering wheel comms Code C1200B
My 2014 GTS suddenly displays multiple dash messages and the steering wheel has lost communications with the rest of the car. No turn signals, horn, high beams, buttons, etc. Display messages are: chassis system, headlight control, and PSM faults. The PIWIS code for the Gateway module (among many others) is "C1200B Communication with steering wheel electronics control unit (CAN chassis)". I've double-checked all fuses. The PIWIS seems to be able to talk to the Gateway module, can send a reset signal or read things like the battery voltage. I have no idea what the "steering wheel electronics control unit" is. Clock spring? Does "everything" run through the clock spring unit? I'm hoping for some diagnostic suggestions or experience here before I break down and turn it over to a Porsche service center.
Steve
Steve
Last edited by strandolph; Dec 1, 2021 at 07:05 PM.
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From: Sold
My 2014 GTS suddenly displays multiple dash messages and the steering wheel has lost communications with the rest of the car. No turn signals, horn, high beams, buttons, etc. Display messages are: chassis system, headlight control, and PSM faults. The PIWIS code for the Gateway module (among many others) is "C1200B Communication with steering wheel electronics control unit (CAN chassis)". I've double-checked all fuses. The PIWIS seems to be able to talk to the Gateway module, can send a reset signal or read things like the battery voltage. I have no idea what the "steering wheel electronics control unit" is. Clock spring? Does "everything" run through the clock spring unit? I'm hoping for some diagnostic suggestions or experience here before I break down and turn it over to a Porsche service center.
Steve
Steve
Thread Starter
Instructor
Joined: Nov 2003
Posts: 230
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From: Bowie, MD
I replaced the battery (Deka 9A49) about a month ago. I just got around to coding the car for the new battery about a week before this happened, but I can't imagine how that might have triggered this. The other threads I found with similar problems had codes triggered by low battery voltage, but no actual loss of functionality (other than start-stop). Mine is different in that, there is evidently no CAN bus communication between the steering wheel electronics and the Gateway Control module. I can't see how a battery issue would cause turn signals, headlight control, horn, etc. to stop working entirely. FWIW, when I coded the new battery, I changed the size from 110AH to 92AH. I've gone through all of the battery "actual values" diagnostics and all seems fine.
Thread Starter
Instructor
Joined: Nov 2003
Posts: 230
Likes: 5
From: Bowie, MD
Following-up for posterity... I didn't want to have to buy a gateway module and/or clock spring and swap parts with potential electrical part return issues, so I brought it to my local dealer to do same. They found the same diagnostic results as I did and then confirmed the actual CAN network signals and chassis as well as all conventional electronics in the steering wheel. Since it was a steering wheel electronics error message, they replaced the clock spring. Initially, they were unable to calibrate and code the new unit. They disconnected the battery and waited long enough for the capacitors in the gateway module to discharge. After that battery reset, they were able to code the clock spring and all is now functional. You don't realize how important turn signals are until you don't have them and become "that guy" who never signals :-).
Would the battery disconnect alone have solved the problem without replacing the clock spring? We'll never know. It's not like they were going to put my old one back in to try and save me the $600 dealer price for it. I originally tried disconnecting the battery as part of my troubleshooting, but maybe I didn't wait long enough (only 5 minutes). The next time I try a battery reset for something, I'm going to wait at least 30 minutes. I don't know how long it takes to discharge the gateway capacitors.
Would the battery disconnect alone have solved the problem without replacing the clock spring? We'll never know. It's not like they were going to put my old one back in to try and save me the $600 dealer price for it. I originally tried disconnecting the battery as part of my troubleshooting, but maybe I didn't wait long enough (only 5 minutes). The next time I try a battery reset for something, I'm going to wait at least 30 minutes. I don't know how long it takes to discharge the gateway capacitors.
