C121c Torque Request Signal Denied? Causes & solutions

The dashboard of your vehicle displays an alert that says “C121c Torque Request Signal Denied.”. Why does it say this? Feeling alone is not necessary. 

It can be confusing to see an error code or alert for the first time. It’s important to handle these messages appropriately and eliminate them in the future. 

C121c Torque Request Signal Denied Causes & solutions

The purpose of this guide is to provide you with an overview of the C121c Torque Request Signal Denied error message. It will be discussed how to identify the problem yourself as well as the cause of this error code. Check out the following article to learn how to get rid of these error codes from your computer. 


What Does The “C121c Code” Mean? 

Once the ABS module has been informed of your message and has performed all necessary functions to determine that there is a problem with the system, which is preventing traction control from working, the C121c Code will appear on your system’s screen. 

Consequently, you will also see an alert indicating that the torque signal request for C121c has been denied. 


How Does The C121c Torque Request Signal Denied Alert Occur?

The “C121c Torque Request Signal Denied” error message is not a problem if you’ve never seen it before.

You may see this alert message on your screen for two main reasons. Detailed explanations of both are provided below.

Anti-lock brake module problem

How Does The C121c Torque Request Signal Denied Alert Occur

This alert message may be caused by a problem with your anti-lock brake module. Your vehicle’s Anti-Lock Brake Module is controlled by this microprocessor. 

It examines your vehicle’s anti-lock braking system as well as 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 brake pressure without skidding.

If the ABS control module malfunctions, the traction control system will not be able to do its job properly, leading to a warning message such as “C121c Torque Request Signal Denied”.

Powertrain Control Module Issue

This alert message may also be caused by the PowerTrain Control Module (PCM) of your vehicle.

The PCM controls your vehicle’s engine, transmission, and other systems based on data received from a variety of sensors. If one of these systems or sensors fails, you may experience problems with the PCM. 

An error alert appears on your car’s dashboard when your traction control system malfunctions. 


Reasons For C121c Torque Request Signal Denied 

While both of the above reasons are the underlying causes of the C121c alert message on the system, it is still difficult to determine what is causing the problem. Three simple methods can be used to determine the problem. 

DTC Check

These steps will help you determine if the error message is caused by a problem with the ABS module.

You can now monitor the ESP Torque Request status to determine whether the ABS module was the issue. 

PowerTrain DTCS Check

Method 1 of recording DTCs for Powertrains follows the same steps as method 2. Your vehicle’s alert message may indicate a problem with the powertrain module if you do this. 

ESP Torque Request Signal Check

You can diagnose the C121c Code error on your computer by following these steps:

  • Your car needs to be started. 
  • Your Allow ESP Torque request can be read and recorded using the scan tool. 
  • There are two ways to interpret ESP torque request signals. 
  • You should perform a PCM test on your car if you suspect a faulty Powertrain module. 
  • The ABS module, on the other hand, is highly likely to have caused the signal if it was present. In this situation, an ABS test is required.

C121c Torque Request Signal Denied: Solutions

After understanding the causes and two methods to determine the actual cause for the alert message, let’s move forward with the fixes.

C121c Torque Request Signal Denied Solutions

ABS Module 

One of the primary reasons you see this alert message is the ABS module, which should be fixed first. 

You cannot repair the ABS module on your own since it is a complicated process. The importance of professional assistance cannot be overstated. 

Wheel speed sensors and a control module make up the main components of an ABS module. Replacement of both of these parts will cost between $1,500 and $3,000 in total. 

A new ABS control module doesn’t require professional assistance. Here’s a YouTube video guide you may find helpful if you want to replace the ABS control module. As a result, replacements will cost less. 

PCM 

Another possibility is that the Powertrain Control Module is not functioning properly, resulting in the error message “C121c Torque Request Signal Denied”. When you have determined that PCM damage is the main cause of this error message alert, your first step should be to visit a nearby garage and have your vehicle’s PCM checked. 

Before considering a PCM replacement, it is crucial to repair the PCM first. In fact, more than half of the Powertrain Control Modules that were replaced required some work. Consult a mechanic who is trustworthy to repair the PC module. 

Damaged Connector Pins 

For your system to display without error messages, you may also need to check the connector pins for damage. A bent or corroded connector pin is usually the cause of the C121c error message, which prevents the traction control system from working. 

Therefore, before giving up, check if the connector pins are all intact and replace them if necessary.

 Can you tell me how much it costs to diagnose code C121c?

The cost of diagnosing Code C121c cannot be determined using one formula, since it depends on several factors. These include the make and model of your vehicle, your local labor rate, and the extent of diagnostics required. The hourly rate for professional automotive diagnostics can range from $80 to $150. 

READ MORE:  What Does KWP2000 Code Mean In Vehicles?

A thorough analysis of the problem and the purchase of specialized equipment may be necessary to determine the cost. Expenses associated with repairs or part replacements should also be considered. 

Your local auto repair shop can provide an accurate estimate if you provide the vehicle’s details and the observed symptoms. By doing so, it is possible to assess the diagnostic costs associated with code C121c in a more accurate manner.


Why Do Fault Codes Exist?

Known as Diagnostic Trouble Codes (DTCs) or fault codes, onboard computers pinpoint abnormalities in various vehicle components.

Modern vehicle diagnostics relies heavily on diagnostic codes to identify performance issues.

Sensors throughout the vehicle’s system detect irregularities that cause fault codes to be generated.

Using specialized tools, such as OBD-II scanners, you can retrieve these codes from your vehicle’s computer.

It is possible to identify problems during diagnostics by coding. The codes represent specific malfunctions or problems.


What Does C121C Mean On A Mitsubishi Outlander?

The C121C code can be caused by a failure of the EBCM (Electronic Brake Control Module) or ABS (Anti-Lock Braking System). Particularly, C121C indicates that a Torque Request Denied Signal has been received.

This code is often displayed when the antilock brakes and traction control of the vehicle are malfunctioning, which is due to the ABS module. ABS module problems can compromise vehicle stability and safety.

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

An examination of the code’s specific conditions is necessary to determine what repairs or adjustments need to be made in order to resolve the problem.

For those unfamiliar with automotive diagnostics, a qualified mechanic should be consulted.


Is There A Way To Fix Code U1424?

The U1424 code is caused by a communication issue with Vehicle Dynamic Control (VDC). In the stability control system of the vehicle, this module plays a vital role. The following steps can be taken to resolve U1424:

Is There A Way To Fix Code U1424 (1)

Scan Diagnostics

A scan using an OBD-II scanner can help you determine what specific conditions triggered the U1424 code. As a result, the root cause of the issue will be identified.

Check The Wiring And Connections

Verify that the connections and wiring of the VDC module are correct. If you find any corrosion or loose connections on the wires, you should inspect them. All connections should be kept clean and debris-free.

Verify Power Supply

Make sure the VDC module receives enough power. Stability control fuses should be checked. Fuse replacement is necessary if any are blown.

Check The VDC Module

Check the wiring and connections of the VDC module itself if they are in good condition. Ensure that the equipment is in good working order. Identifying any issues with the VDC module may require replacing it.

Professional Assistance

In the event that you cannot diagnose and repair a vehicle or if the problem persists after basic checks, it is recommended that you seek professional assistance. Mechanics or dealership service centers can recommend repairs or replacements.

READ MORE:  Best & Worst Ford Expedition Years | Years To Avoid

ECU 128 Code Freightliner [What Is It & Causes]
How To Fix Hill Start Assist Not Available?
How To Change 5.3l Lifters Without Removing Heads?
What Does Cruise Main Mean In A Car? Explained
What Does KWP2000 Code Mean In Vehicles?

Frequently Asked Questions 

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

Engine error codes can be removed using an OBD-II scanner. If the scanner is connected to the OBD-II port of the vehicle, you can clear the codes by selecting the code clearing option and following the prompts. The underlying issue must be addressed before clearing codes to prevent recurring issues.

What is the process for clearing permanent trouble codes?

For permanent trouble codes to be cleared, the underlying issue must be resolved. To clear the codes after repairs are completed, an OBD-II scanner is usually all that is required.

What is the transmission control module error code?

The specific error code for the transmission control module will vary based on the vehicle’s model and make. P0700 is a common transmission error code that indicates a malfunction in the transmission control system. P0xxx codes indicate problems with transmissions as well. You can determine the correct code by using an OBD-II scanner or your vehicle’s service manual.

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

The check engine light may be reset when the battery is disconnected, but the underlying problem will remain. After reconnecting the battery, the light is likely to return if the root cause of the problem persists. Identifying and fixing the problem is recommended before attempting to clear the check engine light.

How safe is it to clear engine codes?

There are safe ways to clear engine codes, but you must first address the underlying issue. By clearing the codes without resolving the problem, you may encounter persistent or recurring issues in the future. Make sure you have made the necessary repairs before clearing the codes in order to prevent ongoing issues.

When do engine codes reset?

Sometimes, following resolution of the underlying issue and clearance of the codes with an OBD-II scanner, the vehicle’s computer may take several drive cycles to complete the necessary self-checks. Through a variety of driving conditions, the computer evaluates the health of the system before resetting it completely.


Conclusion 

There are a number of causes of the error message C121c that appears on the computer system of your vehicle. You’ve also been given some advice on how to resolve the issue in addition to methods for diagnosing it. 

If you would like to remove the error alert, here are some fixes you might try. As a result of reading this guide, you shouldn’t worry about seeing errors on your screen anymore. 

Leave a Comment