C1201 Code Toyota: How To Fix It?

Identifying and resolving a C1201 Toyota code issue can be pretty tricky. This is due to the difficulty of code being generic. Without identifying the specific problem, the code indicates a problem.

As perplexing as it may sound, the C1201 code is. Several factors, such as a gas cap leak, a broken brake light switch, an issue with the engine management system, or a broken wheel speed or oxygen sensor, could cause the light to turn on. However, locating those trouble codes with an OBD2 scanner is simpler.

What Does the C1201 Toyota Code Mean?

The C1201 code might have appeared on your dashboard if you drive a Toyota. Especially if you need help understanding what it signifies, this can be a little mysterious. The Toyota code C1201 denotes an issue with the engine control system.

To figure out what’s wrong with the car, it’s utilized in conjunction with other codes. Depending on the different regulations, it can be related to fuel, anti-lock brake, traction control, or emissions.

The fail-safe function prevents the TRAC and VSC activities if an error is discovered in the truck engine control system and is discovered via the CAN (control area network). The fail-safe is canceled when engine signals are standard input, and the memory cannot store the DTC.

Many Engine Control Units (ECU) are fitted in modern vehicles to provide excellent driving performance. Each Engine Control Unit has a unique diagnostic system to interact with other devices on the network, such as the CAN bus. These devices’ memory will register a fault code if one displays an error or malfunction.

Engineer makes computer diagnostics of the car in auto service.

In addition to the error code, other unit functions will be impacted, or warning lights will be activated. The chassis system’s malfunction causes the DTC C1201 to be set. The electronic stability control or the anti-lock control system could be to blame. The automaker specifies the location and failure of this code.

To better understand what’s going on, running a complete system scan is crucial if you encounter the C1201 error code. This engine error is likely resolved if you look for any other related trouble codes that need rectifying.

C1201 Trouble Code Symptoms

There are various indications that a C1201 mistake is present that you might observe or note.

1.     Traction Light On

The traction control light will turn on as the first and most frequent sign of this issue. When this occurs, it is a sign that something is wrong with the system.

2.     Vehicle Slipping

When driving on slick roads, your car may slide and skid more than usual. This is another reasonably typical symptom that you might experience. This occurs as a result of the traction control system’s malfunction.

3.     The Brake Light is Not Working

Your brake light is not turning on when you press the brake pedal could be another sign. This is a result of the brake light control switches needing to be fixed.

Causes of the C1201 Code

Several different things may cause a C1201 error. The brake light switch is the most typical source of the issue. There may be other causes, such as an issue with the traction control system or the car’s electrical system.

1.     Brake Light Switch

A switch connected to a car’s brakes is called a brake light switch. The switch opens when the brakes are applied, and the brake lights come on. A brake light switch most frequently causes a C1201 error code.

The C1201 error code may show up if the brake light switch is malfunctioning. The switch is typically placed close to the handlebar or pedal.

Car rear lights switched on.

The Brake Control Module receives a signal when the brake light switch is turned on (BCM). The BCM then turns on the brake lights. Other safety elements like the Traction Control System or the Vehicle Stability Control may also be activated using the switch.

Therefore, the VSC and TCS won’t operate if the brake light switch is broken. The C1201 code may be triggered if the BCM fails to receive the indication indicating the brakes are being applied.

The Traction Control System is informed when the brakes are used via brake light switches found on the brake pedal.

The switch’s performance could be the reason why the C1201 error code appears. Keeping the brake light switch in good order is crucial because it is an essential safety component. If it is malfunctioning, you should get your brake light switch fixed as soon as possible.

2.     A Problem With Traction Control System

A Traction Control System issue is another frequent source of a C1201 code. The traction control system prevents your car from sliding around on slick surfaces. The C1201 code may show up if there is an issue with the traction control system.

Each component that makes up the Traction Control System can fail. You should get your Traction Control System fixed as soon as possible if you are experiencing issues.

The following are some of the most frequent Traction Control System component failures:

  • The Brake Light Switch
  • The Traction Control System Sensor
  • The Traction Control System Controller
  • The Traction Control System Switch

Any of these components have a chance of failing, and if they do, the C1201 error code may show up.

3.     Anti Lock Brake System Malfunction

An anti-lock brake system (ABS) safety device keeps the wheels from locking up when the brakes are applied. When a revolution is about to lock up, ABS employs sensors to detect it and only uses the brakes on that wheel.

The C1201 code may be activated if the ABS has an issue. A bad ABS control module, a bad ABS pump, a bad sensor, or low brake fluid are some of the possible causes of ABS issues.

4.     Wet Wheel Speed Sensor

The ABS uses the wheel speed sensor to determine when a wheel is about to lock up. The sensor detects wheel speed and is situated on the wheel’s hub.

The C1201 code may be activated if the sensor becomes wet. The presence of water or other liquids on sensors can make them wet. Driving through a puddle or after just washing your automobile can cause this.

5.     Faulty Oxygen Sensor

The C1201 error code may appear if the oxygen sensor is broken. Age, contamination, or a poor connection are just a few of the factors that might cause oxygen sensors to malfunction. Modern automobiles utilize oxygen sensors to improve the air-fuel ratio. The oxygen sensor generates a voltage signal by the amount of oxygen in the exhaust stream.

An old Oxygen sensor ready to be replaced.

The computer in the car uses this signal to modify the air-fuel ratio to maximize efficiency and performance. A vibrant air-fuel mixture can result in higher emissions, worsened fuel efficiency, and less power. When the mixture is too lean, harm to the engine may result.

How Serious is the C1201 Code?

The ECM cannot communicate with the Electronic Stability Control System and the Anti-lock Braking System when a C1201 code is present. It is crucial to get them mended as soon as possible because this could cause accidents.

Your car could suffer catastrophic damage if the C1201 error code is not addressed. Your car might start to slide on slick roads, which is one of the most frequent issues that might arise. This carries a high risk of injury and mishap.

When you press the brake pedal, the brake light might not turn on as another potential issue. This carries a high risk of hazard and the potential for mishaps. To prevent any significant problems, it is crucial to resolve the C1201 error code as soon as possible.

What Repairs Can Fix the C1201 Toyota Code?

You must utilize three linked codes to erase the C1201 error code. They are the C1201 Engine Control System Malfunction, the P0455 Evaporator Emission Control (leak identified, a big leak or no purge flow), and the P0441 Evaporator Emission Control System Improper Purge Flow.

The P0 codes indicate gas leaks in the system.

The leading cause is a leaky gas cap, though it might also be in the line near the charcoal canister or the filler torque. Either the cap has worn out or it is attached incorrectly. The C1201 code instructs the vehicle to lessen VSC and traction while turning on the “Check Engine Light.”

As a result, the C1201 code alerts you to issues, mainly when the other two systems do. Because the P0 codes are the root of the problem, you can fix it by changing them.

What Repairs Can Fix the C1201 Toyota Code?

The gas lid cannot be changed to resolve the C1201 error code. Therefore, you must determine the precise meaning of the C1201 code on your car and resolve the issue. The idea that a new gas cap can enable the car to turn off the check engine light is untrue and deceptive. If the issue still exists, you should try to fix it before choosing a costly solution.

The following remedies could help with this issue:

  • You must inspect the gas cap, tighten it, and reset all the codes.
  • Check to see if the gas cap leaks; clean and lubricate the seal before clearing the codes.
  • If none of the abovementioned suggestions work, you must purchase an OEM aftermarket gas lid. However, remember that a low-quality cap won’t solve the issue, so use a high-quality one instead.
  • While purchasing a new cap can often resolve the problem, occasionally, it won’t. This indicates that the light can reappear later with more significant issues. What are you to do now, then? As a result, you can get a brand-new original cap from the aftermarket.
  • Make sure the item you are purchasing has a genuine seal cap. Replace the original voila and lid with the new seal, and all of your issues will be solved. After you’ve finished repairing, use a code reader or unplug your batteries to erase all the codes from your computer.

C1201 Toyota Fixing Cost

Depending on what caused the C1201 error, different solutions have different costs. For instance, the expense will be small if the gas cap needs to be tightened or replaced. Your costs for such a repair or replacement will be under $20.

However, the cost would be substantially higher if you need to bleed the brakes or replace the ABS pump. A new ABS pump will set you back at least $300.

Most of the time, nothing needs to be replaced. The code only displays because your car has recently undergone maintenance, and a sensor has tripped. You bring your automobile to the shop, and the mechanic will connect it to a scanner.

The mechanic will then reset the code. You will pay between $100 and $150 for this. Ultimately, taking your car to a trained mechanic or dealership for diagnosis is the best approach to acquiring an exact pricing estimate.


The yaw sensor, ABS, and declaration sensor provide the Toyota stability control system data. The motor speed sensors provide information to the ABS. These sensors frequently fail, and they often set an ABS fault code when they do.

If you receive a C1201 code after checking, you do not need to continue looking into the wheel speed sensor issues. The automobile swerves, skids, or loses control if the Toyota vehicle stability control system detects a wheel rock. When this occurs, it tries to control it by activating the ABS brakes and reducing engine power.

Taking your car to a trained mechanic or dealership for analysis is the best way to determine what is setting off the code on your vehicle. They can accurately identify the problem and suggest the best line of action.

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About Brock Rangel

Hi, I am Brock, and I am the lead editor/photographer for TheCarColony. I have been a mechanic for over 14 years now, and I am here to spread my car knowledge across the web!