Hi Guys
For about a year or so, intermittently, my 2010 Grand Caravan would stall out. It was usually with a cold engine, just with-in a mile from home (except once) and always under 25 mph. So it happened again yesterday and I took it to an Avanced Auto Store to get the code read. It came up with C121C.

All I can find on the web is something about Torque request signal denied.

Anyone want to comment on this?? I do have an appointment on Monday to take care of another issue. So they also get to hear about this.

Anything you can think of is going to be very helpful to me.

 

Cold engine stalls in my experience were always fuel system related, either the filter is clogged up or the pressure regulator is failing to operate correctly. BUT, given the provided engine code, it could be something much more sinister, maybe transmission related. Have the transmission control module checked for any extra codes, it might give you a hint as to what's going on. If the trans seems clean, then I would assume fuel starvation.

(I could be wrong about the TCM storing codes separately and not sharing them with the main ECM, so if anyone knows more about this generation feel free to correct me)

 

What did you find out? I have the same issue, same code. I think there is a chance that it is fuel related. I have tried cleaning the system with Seafoam. I ran it through the system and then it failed to start the next time. Perhaps something dislodged?

 

check out frogbandit post I posted there too


http://ww2.justanswer.com/uploads/dr..._document1.pdf

 

C121C-TORQUE REQUEST SIGNAL DENIED

For a complete wiring diagram Refer to the Wiring Information.

• When Monitored:
With the engine running.

• Set Condition:
When the Powertrain Control Module indicates, for an extended period of time, that engine management relevant for Automatic Yaw Control/Traction Control System control can not be accomplished.







Possible Causes


ANTI-LOCK BRAKE MODULE
POWERTRAIN CONTROL MODULE


1.CHECK FOR A DTC C121C-TORQUE REQUEST SIGNAL DENIED







NOTE: This DTC must be active for the results of this test to be valid and this DTC may set while driving under severe load conditions.




1. Turn the ignition on.




2. With the scan tool, read and record DTCs.




3. With the scan tool, read and record Environmental Data to help identify the conditions in which the DTC was set.




4. With the scan tool, erase DTCs.




5. Cycle the ignition switch from off to on.




6. Start Engine.




7. With the scan tool, read and record DTCs and monitor ESP Torque Request status.


Does the scan tool display: C121C-TORQUE REQUEST SIGNAL DENIED?

Yes

•Go To 2

No

•Perform the ABS-INTERMITTENT CONDITION TEST (Refer to 28 - DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure).




2.CHECK THE POWERTRAIN DTCS





1. With the scan tool, read and record Powertrain DTCs.


Were any Powertrain related DTCs found?

Yes

•Repair the Powertrain Diagnostics (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Diagnosis and Testing).

No

•Go To 3




3.ESP TORQUE REQUEST SIGNAL





1. Engine started.




2. With the scan tool, read the Allow ESP Torque Request status bit.


Was the Allow ESP Torque Request showing NOT set?

Yes

•Replace the Powertrain Module in accordance with the Service Information.
•Perform POWERTRAIN VERIFICATION TEST (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

No

•Replace the Anti-Lock Brake Module in accordance with the Service Information.
•Perform ABS VERIFICATION TEST (Refer to 28 - DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure).