C1201 Code: Meaning, Symptoms, Causes, & Fixing

C1201 Code Definition

The C1201 code stands for “Engine Control System Malfunction.”

What Does the C1201 Toyota Code Mean?

Toyota code C1201 indicates an issue in your engine control system. This trouble code is utilized in conjunction with other trouble codes to find the issue in the car.

According to the other existing codes, the C1201 trouble code may also indicate a problem with your vehicle’s traction control system (TRAC), anti-lock brake (ABS) system, or fuel system. Therefore, when the C1201 code is triggered, you should perform a full system scan to find the main issue. You should first fix the other existing trouble code, and most likely C1201 trouble code will be fixed itself.

C1201 Code

If your engine control system is not functioning properly, the Control Area Network (CAN) of your vehicle stops working of the vehicle stability control (VSC) system and traction control system (TRAC) system as part of a fail-safe system.

Even when these systems are working properly, problems can still arise. In such conditions, you should focus on the trouble codes that aren’t generic.

Symptoms of the C1201 Trouble Code

  • Check engine light is illuminating
  • Traction control light illumination
  • Your engine is consuming more fuel than usual
  • Poor engine performance
  • Stability control issues

Causes of the C1201 Code

  • A faulty brake light switch is one of the most common causes of the C1201 code.
  • Issues with the traction control system
  • Bad O2 sensor
  • A loose or damaged fuel tank cap
  • Damaged or corroded harness or wiring
  • Leaked EVAP system

How to Diagnose the C1201 Toyota Trouble Code

To diagnose the C1201 code, you must have the following basic tools:

  • Basic hand tools
  • OBD-II scanner
  • Multimeter
  • Electrical contact cleaner
  • Auto repair manual

Follow the below-given steps to fix the C1201 code:

  • First of all, verify the existence of the C1201 code using a scan tool. Record all the existing codes by using the scan tool.
  • Analyze the data of the scan tool to find the main issue.
  • Clear the codes and perform a test drive. If the code returns, move forward for further inspection.
  • Properly check the reluctor ring of the wheel speed sensor for a fault.
  • Properly inspect the electrical connections and wires of the wheel speed sensor for damage.
  • Inspect the O2 sensor for damage.
  • Inspect the brake light switch for a problem.
  • Inspect the EVAP system for damage or leak.
  • Inspect the traction control system for faults.
  • Once the issue is resolved, clear the codes once again and take a test drive. 

Common C1201 Code Diagnosis Mistakes

  • Not fixing the other existing trouble codes before fixing the C1201 Toyota or Lexus code.
  • Not clearing the ECM/PCM memory after fixing the issue
  • Replacing the traction control system or O2 sensor before inspecting the wiring or harness.

What repairs can fix the C1201 Code?

  • Replacing the damaged or loose fuel tank cap
  • Replacing the faulty O2 sensor
  • Repairing the leaked EVAP system
  • Repairing or replacing the damaged harness or wiring
  • Fixing or replacing the e bad traction control system

Estimated Repair Cost of C1201 Code

To fix the C1201 code, you can expect a variety of costs involved. Following are a few parts that you may need to repair or replace to fix the C1201 code.

PartsCost
Fuel tank cap replacement$5 to $30
O2 sensor replacement$140 to $560
EVAP system leak fixing$90 to $650
Wiring or harness repairing$40 to $1,500

FAQ Section

Where is the brake light switch located?

The brake light switch of the vehicle is usually located on the brake pedal. Remove the brake pedal to access the brake light switch.

Can you drive with the C1201 code?

A full diagnosis is required to determine if you can drive with the C1201, as there are many possible causes of the C1201 code. However, it is not recommended to drive with this code. When your vehicle triggers this code, you should fix it as early as possible.

What is an engine EV control system?

The EV control system of your vehicle handles different types of engine torque command calculations and system control according to the input signals obtained from the various switches and sensors. The EV ECU is usually connected with diagnostic functions and fail-safe functions of your vehicle.

How Serious is the C1201 Code?

The C1201 code is considered a serious trouble code. This code indicates that your ECM is failed to work with the Anti-lock Braking System and Electronic Stability Control System. Driving with this code may cause a vehicle accident. Therefore, you should fix it immediately.

Can I start my car without ECM?

No, you can’t start your vehicle without a proper operating ECM. As your ECM goes bad completely, your car will lose control of the engine management and will not be able to start or drive. Your vehicle engine can start but will not start without significant input from the ECM.

What are the symptoms of a bad ECM?

  • Check engine light illumination
  • Poor engine performance
  • Rough idling
  • Poor fuel economy
  • Hard to start the engine, or engine is not starting at all
  • Engine shuts off
  • Engine stalling
  • Engine misfiring

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