15 Jeep Wrangler C121C. A verified repair using a flash update?

Sam Mobile Technician Michigan Posted   Latest   Edited  
Case Study
2015 Jeep Wrangler Sport 3.6L (G ERB) 6-spd (NSG370)
Torque Request Denied

I do mobile programming and am amazed at some of the requests I get. (that can be a different discussion) I get a call from a shop that is a pretty regular customer with relatively good results. If you do mobile programming you know what I mean. 

I get a call to program an ABS module on a 15 Jeep wrangler. New unit from dealer. I usually do not ask why, and I also did not this time. I get to said shop, and initialize the ABS module. All goes well until I am returning from the drive required. I get a traction control light. Check ABS codes. I have a C121C Torque request denied. The diagnosis is very basic. It comes down to either a new ABS module or a New PCM. 



I see that there are updates for PCM and TCM. These are additional charges, and there is not a bulletin stating what this will repair. It is a roll of the dice for sure. After some discussion with the shop. The decision is made to go ahead and do the updates. There is also an oil control code. I do not remember for sure what it was. The shop was going to investigate after I was done. 

After a 10 mile test drive it is decided both codes have been repaired by a PCM/TCM update. I am not sure which fixed it. They were both way out of date, 

I just fine it interesting, AllData, Identifix both had the code description and diagnosis as module replacement. Tech authority did not even list the code that I could find. No suggestion for an update. Makes me wonder if it needed a ABS module at all. I am going with NO. I will never know for sure. 

Hope this helps someone in the future. 


Tony Owner/Technician

The trouble tree looks very simple. It is probably accurate, they usually are. That said… Module replacement seems extreme for a code like that. I'm familiar with codes that directly specify communication faults between modules, actual internal module faults, and disable requests. Your code description sounds like a disable request, which is usually because the PCM has an issue and doesn't want…

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Eddy Business Development Manager

TSB#18-078-18 addresses the oil code with a PCM update as you mentioned. TSB also says there may be a drivability issue associated with this particular problem.

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