C121C: Torque request signal denied, stored in the ABS module (Chrysler, Jeep, Ram)

ABS/ESC torque request signal denied

Severity: Inspect soon

The ESC warning light comes on with this code. FCA's owner's manual says an ESC light that stays on means a malfunction in the stability control system and to see a dealer as soon as possible. Stability and traction control may not work, and the engine fault behind the code can cause power loss.

It gets more serious if:

Stop: The engine stalls, shuts off or loses power while driving. Owners report Town and Country minivans shutting down on the road and Rams losing power while towing with this code. Pull over safely and have it diagnosed before driving on.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

C121C in short

On Chrysler, Jeep and Ram vehicles, C121C means the ABS/stability control module asked the engine computer to cut or change engine power and was refused. The ESC light comes on and stability control may not work. The root cause is usually an engine fault or software conflict, so get it diagnosed soon.

To control wheel spin and skids, the ABS/ESC module can ask the engine computer (PCM) to reduce engine torque. Service information quoted on a Jeep forum says C121C sets when the PCM reports, for an extended time, that it cannot carry out the engine management needed for stability and traction control.

So C121C is usually a messenger. Owners and technicians report it with engine codes such as throttle faults (P2110, P2173), cam sensor faults (P0344) or turbo boost faults, and the fix lies with that engine problem. On the 2017 Chrysler Pacifica, FCA bulletin 18-057-16 says a PCM software calibration conflicts with the ABS module programming and a PCM reflash corrects it.

FCA also issued bulletin S2208000084 for the ESC lamp with C121C-00 on 2021–2022 Gladiators. We have only read its summary.

Pick your make

C121C is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

Most likely causes

Cause 1: Engine or throttle fault stopping the PCM from controlling torque
Supported by vehicle data
Why it ranks here
Service information quoted on a Jeep forum says the code means the PCM could not perform the engine management stability control asked for. Technician posts and owner reports show it alongside throttle, cam sensor and turbo codes.
What would change this
Rises if engine codes (P-codes) are stored, the check engine or throttle light is on, or the engine has lost power. Falls if no engine codes are present.
How to test the engine control module (ecm / pcm)
Cause 2: PCM software conflicting with ABS module programming (2017 Pacifica)
Supported by vehicle data
Why it ranks here
FCA bulletin 18-057-16 says C121C-00 on the 2017 Pacifica is caused by a PCM calibration that conflicts with the ABS module and is fixed by reprogramming the PCM.
What would change this
Rises on a 2017 Pacifica without the update. Falls on other vehicles or after the reflash.
How to test the engine control module (ecm / pcm)
Cause 3: ABS/ESC module fault
Possible — needs testing
Why it ranks here
The quoted service information lists the ABS module as a possible cause, after the PCM side.
What would change this
Rises only if the engine side and any bulletins are ruled out and the code returns.
How to test the brake system control module (abs module)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Have codes read from both the engine computer (PCM) and the ABS module, and write down every code.
Low riskTool: scan tool with ABS access
- IfEngine codes are stored too, such as throttle, cam sensor or boost codes
  It meansDiagnose those first; C121C often clears once the engine fault is fixed.
  Go to step 3 Points to: Engine or throttle fault stopping the PCM from controlling torque
- IfC121C is the only code
  It meansCheck for a software bulletin for the vehicle.
  Go to step 2
Step 2: Ask a dealer whether a software bulletin for C121C applies to your VIN, such as 18-057-16 (2017 Pacifica) or S2208000084 (2021–2022 Gladiator).
Low riskTool: phone call to a dealer
- IfA bulletin applies and has not been done
  It meansThe software update is the likely fix.
  Points to: PCM software conflicting with ABS module programming (2017 Pacifica)
- IfNo bulletin applies
  It meansThe engine and ABS sides need diagnosis.
  Go to step 3
Step 3: Have a technician diagnose any engine codes first, then check communication between the PCM and ABS module using FCA service information, and clear and recheck.
Best left to a shopTool: factory-level scan tool and service information
Warning:This involves the stability control and engine control systems. Leave it to a qualified technician, and do not keep driving if the engine stalls or loses power.
- IfAn engine fault is found and repaired, and C121C does not return
  It meansThe engine fault was the cause.
  Points to: Engine or throttle fault stopping the PCM from controlling torque
- IfThe engine side is clean and C121C returns
  It meansThe ABS module is suspect.
  Points to: ABS/ESC module fault

Symptoms

ESC or traction control light on
Check engine or electronic throttle warning light on
Engine stalls, shuts off or loses power while driving Gets more serious: stop and have it checked.
Reduced power (limp mode) Gets more serious: stop and have it checked.

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

PCM software / engine sensors:Fixes reported range from a PCM software update to repairing the underlying engine fault. Avoid replacing the ABS module until the engine side is ruled out. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Chrysler

2017 · Pacifica
Supported by vehicle data
FCA bulletin 18-057-16: C121C-00 from a PCM calibration conflict, fixed by a PCM reflash. Whether it is still current is not verified.
2008–2010 · Town and Country
Supported by vehicle data
Owners report the van shutting down while driving with C121C stored; one dealer found only C121C.

18-057-16Status unverified
Powertrain diagnostic and system enhancements (C121C-00 torque request signal denied)
2017pacifica · issued May 11, 2016 · NHTSA 10181480
C121C-00 in the ABS module is caused by a PCM calibration that conflicts with the ABS module programming; reprogramming the PCM corrects it.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Jeep

2021–2022 · Gladiator
Supported by vehicle data
FCA bulletin S2208000084 covers the ESC lamp with C121C-00. Whether it is still current is not verified.
2021–2025 · Wrangler
Supported by vehicle data
Owners report C121C in the ABS module stored with throttle codes such as P2173 in the PCM.

S2208000084Status unverified
ESC lamp on, DTC C121C-00 torque request signal denied
2021–2022gladiator · issued May 31, 2022 · NHTSA 10212348
Covers the ESC lamp with C121C-00 on the Gladiator; only the NHTSA summary was read.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ram

2021–2023 · 1500
Supported by vehicle data
Owners report C121C with loss of power, alongside turbo boost or throttle codes.

No curated relationships for C121C yet.

All ABS, traction and stability control codes

C121C questions

Is C121C a brake problem?

Usually not. It is stored in the ABS module, but it means the engine computer could not carry out a torque request. Engine faults or software are the usual causes.

Can I keep driving with C121C?

If the engine runs normally, drive gently and get it checked soon, because stability control may not work. If the engine stalls or loses power, pull over safely and have it diagnosed.

Sources and review

2022 Ram 2500/3500 Owner's Manual: ESC activation/malfunction indicator light — FCA US LLC
NHTSA complaint 11193222: 2010 Chrysler Town and Country, dealer code C121C — NHTSA Office of Defects Investigation
NHTSA complaint 11690166: 2021 Ram 1500, C121C-00 with P00AF-00 — NHTSA Office of Defects Investigation
Owner complaints mentioning C121C on Chrysler, Jeep, Dodge and Ram vehicles — NHTSA Office of Defects Investigation
JeepKJ forum: C121C on a 2007 Jeep Liberty (moderator quoting service information) — JeepKJ.com forum
iATN TechMail: C121C DTC on a 2005 Chrysler 300 3.5L — International Automotive Technicians Network , June 1, 2012
iATN TechMail: C121C DTC on a 2011 Ram 1500 5.7L — International Automotive Technicians Network
NHTSA complaint 11755722: 2025 Jeep Wrangler, dealer finds C121C in the ABS module with P2173 — NHTSA Office of Defects Investigation
Chrysler 18-057-16: 3.6L powertrain diagnostic and system enhancements (C121C-00 torque request signal denied) — FCA US / NHTSA , May 11, 2016
Jeep S2208000084: ESC lamp on, DTC C121C-00 torque request signal denied — FCA US / NHTSA

Last reviewed: October 15, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Pick your make

Most likely causes

Cause 1: Engine or throttle fault stopping the PCM from controlling torque

Cause 2: PCM software conflicting with ABS module programming (2017 Pacifica)

Cause 3: ABS/ESC module fault

What to test first

Step 1: Have codes read from both the engine computer (PCM) and the ABS module, and write down every code.

Step 2: Ask a dealer whether a software bulletin for C121C applies to your VIN, such as 18-057-16 (2017 Pacifica) or S2208000084 (2021–2022 Gladiator).

Step 3: Have a technician diagnose any engine codes first, then check communication between the PCM and ABS module using FCA service information, and clear and recheck.

Symptoms

How to fix

Parts and cost context

On your vehicle

ChryslerYour car

JeepYour car

RamYour car

Related codes

C121C questions

Sources and review

Chrysler

Jeep

Ram