C121c Torque Request Signal Denied? Causes & solutions

The dashboard of your vehicle displays the message “C121c Torque Request Signal Denied.”. Do you know what it means? Feeling alone is unnecessary. 

Error codes and alerts can be confusing the first time you see them. What is important is how you handle these messages in the future and eliminate them. 

As you proceed through this guide, we’ll explain what C121c Torque Request Signal Denied means. There will be a discussion of the cause of this error code as well as some techniques for determining what’s wrong on your own. Continue reading to learn how to remove these error codes from your computer. 

What Does The “C121c Code” Mean? 

C121c Torque Request Signal Denied

After the ABS module has already received your message and performed all necessary functions to determine that traction control is having problems, the C121c Code will appear on your system’s screen. 

C121c will also display an alert indicating that the torque signal request was denied. 

How Does The C121c Torque Request Signal Denied Alert Occur?

There’s no need to worry if you’ve never seen the “C121c Torque Request Signal Denied” error message before; we’ll explain it all.

It is possible for this alert message to appear on the screen of your computer for two major reasons. I will explain both in detail here.

Anti-lock brake module problem

It is possible that your anti-lock brake module is malfunctioning and causing this alert message. Your vehicle’s Anti-Lock Brake Module is controlled by this microprocessor. 

In addition to the anti-lock braking system, it examines the hydraulic brake system and wheel sensors as part of the diagnostic process. The car needs to be locked at the right time in order to determine when to release the brake pressure without skidding.

When the ABS control module malfunctions, the traction control system cannot function correctly, resulting in the “C121c Torque Request Signal Denied” warning.

Powertrain Control Module Issue

You may also see this alert message on your screen because of your vehicle’s PowerTrain Control Module (PCM). 

PCMs control engines, transmissions, and other vehicle systems using data from sensors located throughout your vehicle. Even if one of these systems or sensors is malfunctioning, you may experience problems with the PCM. 

In this case, your car’s traction control system malfunctions, resulting in an error alert on its dashboard.

Reasons For C121c Torque Request Signal Denied 

In spite of the fact that both reasons listed above are the root causes of C121c alert messages on the system, it’s still difficult to determine what the problem is. These three simple methods can help you identify the problem. 

DTC Check

Here are the steps you can take to determine if the error message is caused by an ABS module problem.

  • Turn the ignition key in the ignition slot. 
  • Using the scan tool, DTCs can be read and noted. 
  • To identify the conditions under which DTCs were set, environmental data should be recorded. 
  • Using the scan tool, remove all DTCs and turn on the ignition. 
  • Start the engine of your vehicle. 
  • DTCs will be measured and recorded using the scan tool. 

Now you can monitor the ESP Torque Request status to determine whether the ABS module was the culprit. 

PowerTrain DTCS Check

As with method 1, recording Powertrain DTCs follows the same procedure. This can help you determine if there is a problem with the Powertrain module causing the alert message to appear on your vehicle. 

ESP Torque Request Signal Check

These steps will help you diagnose your computer’s C121c Code error:

  • Your car needs to be started. 
  • Your Allow ESP Torque request status can be read and recorded using the scan tool. 
  • There are two ways to interpret torque requests from an ESP. 
  • Having a faulty Powertrain module can cause the signal not to be set, so you should have your car tested for a faulty PCM. 
  • Conversely, if the signal was present, it is highly likely that the ABS module was to blame. The system must be tested for ABS in this case.

Read: What Does Cruise Main Mean In A Car?

Solutions For C121c Torque Request Signal Denied

C121c Torque Request Signal Denied

Having identified the causes and two ways to determine the real reason for the alert message, let’s move on to the fixes.

ABS Module 

This error message is often caused by a malfunctioning ABS module, which should be repaired first to fix the problem. 

You cannot repair the ABS module yourself since it is a complicated procedure. The importance of professional assistance cannot be overstated. 

A control module and wheel speed sensors are the two main components of an ABS module. Replacement of both of these components will cost between $1,500 and $3,000. 

Replacement of the ABS control module doesn’t require professional assistance. Here is a YouTube video guide you may find helpful if you would like to replace the ABS control module. Saving money on replacements will be possible this way. 


Second, the Powertrain Control Module may be malfunctioning, leading to the error message “C121c Torque Request Signal Denied”. In the event you have already determined that PCM damage is the major cause of this error message alert, your first step should be to take your vehicle to a local garage and get it checked. 

Prior to considering a replacement, it is imperative that the PCM is repaired first. There was some repair needed on more than 50% of the Powertrain Control Modules that were replaced. Consult a trustworthy mechanic about repairing the PC module. 

Damaged Connector Pins 

If the error message remains on your system’s display, you may need to check the connector pins for any damage. Bending or corroded connector pins usually prevent the traction control system from working, resulting in the C121c error. 

Be sure to check the connector pins for wear before giving up.

 How much does diagnosing code C121c cost?

Several factors influence the cost of diagnosing Code C121c, including the vehicle’s makes and models, local labor rates, and the extent of the diagnostic process. There is no one-size-fits-all formula for determining the cost of diagnosing Code C121c. Professional automotive diagnostic services can cost between $80 and $150 per hour. 

In order to determine the cost, specialized equipment may need to be purchased and the problem in-depth analyzed. In addition, potential repair or replacement expenses should be considered. 

If you provide your local auto repair shop with your vehicle’s details and symptoms, you will receive an accurate estimate. By doing so, it is possible to estimate more precisely the diagnostic costs associated with code C121c.

Why Do Fault Codes Exist?

An onboard computer generates a fault code that pinpoints abnormalities in various vehicle components, called Diagnostic Trouble Codes (DTCs).

For insight into performance issues, modern vehicle diagnostics heavily rely on diagnostic codes.

Sensors throughout the vehicle’s system detect irregularities that generate fault codes.

The codes can be retrieved from a vehicle’s computer using specialized tools, such as OBD-II scanners.

During diagnostics, coding helps identify problems systematically. Codes represent specific malfunctions or problems.

What Does C121C Mean On A Mitsubishi Outlander?

C121c Torque Request Signal Denied

Mitsubishi Outlanders with the C121C code can have problems with their EBCMs (Electronic Brake Control Modules) or ABS systems. Torque Request Denied Signals are indicated by C121C.

In vehicles with antilock braking systems and traction control, this code is often displayed when the ABS module malfunctions. In the event of an ABS module malfunction, safety and stability of the vehicle can be compromised.

To diagnose the cause and solution of the C121C code, an OBD-II scanner should be used.

The specific conditions of the code must be analyzed in more detail in order to determine the necessary repairs or adjustments.

In case you are unfamiliar with automotive diagnostics, you should consult a mechanic.

Read: What Does KWP2000 Code Mean In Vehicles?

How To Fix Code U1424?

U1424 is triggered by a communication problem in Vehicle Dynamic Control (VDC). The stability control system of a vehicle relies heavily on the performance of this module. In order to resolve U1424, follow these steps:

Verify Power Supply

Make sure the VDC module receives enough power. Stability control fuses should be checked. Check for blown fuses and replace them if necessary.

Check The VDC Module

Depending on whether the wiring and connections are in good condition, you might consider inspecting the VDC module itself. Verify the device is not damaged or malfunctioning. There may be a need to replace the VDC module if issues are identified.

Professional Assistance

Whenever a vehicle can’t be diagnosed and repaired by yourself, or if the problem persists after basic checks, you should seek professional assistance. Mechanics or dealership service centers can recommend repairs or replacements.

Scan Diagnostics

The U1424 code can be verified by performing an OBD-II scan using an OBD-II scanner. The problem can then be identified by identifying its root cause.

Check The Wiring And Connections

Verify the wiring and connections of the VDC module. Wires should be examined for corrosion, loose connections, and damage. Clean and maintain a debris-free environment around all connections.

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Read: Code 89 Vauxhall Mokka

Frequently Asked Questions

What is the process for clearing permanent trouble codes?

For permanent trouble codes to be cleared, it is usually necessary to repair the underlying issue. As soon as the repairs are complete, all that is usually required to clear the codes is a simple OBD-II scanner.

What is the best way to clear my engine error code?

Engine error codes can be removed using the OBD-II scanner. Connect the scanner to the vehicle’s OBD-II port, choose the code clearing option, and follow the prompts. The underlying issue must be addressed before clearing codes to prevent recurring issues.

What is the transmission control module error code?

Transmission control module error codes vary depending on the model and make of the vehicle. There are specific P0xxx codes that indicate transmission problems, along with P0700, which indicates transmission control system malfunction. Check your vehicle’s service manual or use an OBD-II scanner to determine the proper code.

What happens if you disconnect the battery and then reconnect it?

Disconnecting the battery will reset the check engine light, but not fix the underlying problem. Reconnecting the battery is unlikely to resolve the problem if its root cause remains. It is recommended to diagnose and fix the problem before attempting to clear the check engine light.

How safe is it to clear engine codes?

The underlying problem must be addressed before engine codes can be cleared safely. It is possible to experience persistent or recurring problems in the future if you clear the codes without resolving the problem. You should make the necessary repairs before clearing codes to prevent ongoing issues.

When do engine codes reset?

A vehicle’s computer may not complete the necessary self-checks until several drive cycles have passed after the underlying issue has been resolved and the codes have been cleared. During a range of driving conditions, the computer evaluates the system’s health before resetting it.


C121c error messages appear on your vehicle’s computer system for a number of reasons, as we discussed in this guide. Our advice includes both methods for diagnosing the problem and suggestions for resolving it. 

The final point we would like to make is to point out some fixes for removing the error alert. By reading this guide, you shouldn’t see any errors on your screen anymore. 

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