C120B Toyota Code - Ignition Supply Voltage Low
Quick Answer
The Diagnostic Trouble Code (DTC) will be set when the Master Cylinder Pressure Sensor power supply voltage decrease occurs, or a history of voltage decrease exists, and defective Master Cylinder Pressure Sensor output continues for 1 second or more. Common causes include Faulty Master Cylinder Pressure Sensor, Master Cylinder Pressure Sensor harness is open or shorted, Master Cylinder Pressure Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- C120B Toyota indicates Ignition Supply Voltage Low.
- Common causes
- Common causes include Faulty Master Cylinder Pressure Sensor, Master Cylinder Pressure Sensor harness is open or shorted, Master Cylinder Pressure Sensor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code C120B Toyota Description
What are the Possible Causes of the DTC C120B Toyota?
- Faulty Master Cylinder Pressure Sensor
- Master Cylinder Pressure Sensor harness is open or shorted
- Master Cylinder Pressure Sensor circuit poor electrical connection
- Faulty Skid Control ECU (Brake Actuator Assembly)
How to Fix the DTC C120B Toyota?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the C120B Toyota code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Toyota Models
- C120B 2013 Toyota RAV4 — Ignition Supply Voltage Low
- C120B 2014 Toyota RAV4 — Ignition Supply Voltage Low
- C120B 2015 Toyota RAV4 — Ignition Supply Voltage Low
- C120B 2016 Toyota RAV4 — Ignition Supply Voltage Low
- C120B 2017 Toyota RAV4 — Ignition Supply Voltage Low
- C120B 2018 Toyota RAV4 — Ignition Supply Voltage Low
Frequently Asked Questions about C120B Toyota Code
1. What does the OBDII code C120B mean on a Toyota?
C120B indicates "Ignition Supply Voltage Low," meaning the vehicle's electronic control module (ECM) is detecting insufficient voltage in the ignition supply circuit.
2. What are the common symptoms of the C120B code?
Symptoms include illuminated warning lights like the ABS or traction control light, difficulty starting the car, or intermittent electrical issues.
3. What causes the C120B code to appear?
Common causes include a weak or failing battery, a faulty ignition switch, damaged wiring or connectors in the ignition circuit, or a failing alternator.
4. Can I still drive my Toyota with the C120B code?
While you may be able to drive, it's not recommended as the low voltage could lead to further electrical issues or even prevent the car from starting.
5. How do I diagnose the C120B code?
Start by checking the battery voltage and alternator output. Inspect wiring and connectors for damage or corrosion. Use a multimeter to test the ignition circuit for proper voltage.
6. How do I fix the C120B code on my Toyota?
Repairs may include replacing a weak battery, repairing damaged wiring, cleaning corroded connectors, or replacing a faulty ignition switch or alternator.
7. What tools are needed to troubleshoot the C120B code?
You'll need a digital multimeter, an OBDII scanner, and basic hand tools to inspect and test electrical components.
8. Can a low battery cause the C120B code?
Yes, a low or failing battery is one of the most common reasons for the C120B code, as it can result in insufficient voltage to the ignition circuit.
9. How much does it typically cost to fix the C120B code?
Costs vary depending on the issue. Battery replacement may cost $100-$300, while alternator repairs could range from $300-$800. Wiring repairs are typically less expensive unless extensive damage is present.
10. Will clearing the C120B code with a scanner fix the problem?
Clearing the code will only reset the warning temporarily. The underlying issue must be resolved to prevent the code from returning.
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