AutoCodes – Scion – C120B Scion

C120B Scion 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 Scion 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.

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Code Popularity 223

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jan 18, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C120B Scion Description

OBDII Code C120B Scion - Ignition Supply Voltage Low - AutoCodes.com — C120B Scion Code - Ignition Supply Voltage Low

What does this mean?

What are the Possible Causes of the DTC C120B Scion?

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 Scion?

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 Scion 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.

Need more information about the C120B Scion code?

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Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C120B Scion Code

1. What are the common symptoms of OBDII code C120B (Ignition Supply Voltage Low) in a Scion?

- Common symptoms include difficulty starting the vehicle, rough idling, engine stalling, and the illumination of the check engine light.

2. What are the possible causes of OBDII code C120B in a Scion?

- The code can be triggered by issues such as a faulty ignition switch, a weak battery, poor electrical connections, or a malfunctioning alternator.

3. How can I diagnose the source of the Ignition Supply Voltage Low issue in my Scion?

- To pinpoint the cause, you can use a multimeter to test the battery voltage, check the ignition switch operation, inspect the wiring for any damage, and verify the alternator's output.

4. Can a weak battery cause the C120B code in a Scion?

- Yes, a weak or failing battery can lead to low ignition supply voltage, triggering the C120B code in the Scion's OBDII system.

5. What are some repair tips for addressing OBDII code C120B in a Scion?

- Repair tips include replacing a faulty ignition switch, testing and potentially replacing the battery, ensuring all electrical connections are secure, and addressing any alternator issues.

6. Is it safe to continue driving my Scion with the C120B code present?

- It is not recommended to continue driving the vehicle with the C120B code, as it can lead to potential issues such as stalling or complete engine failure.

7. How urgent is it to address the Ignition Supply Voltage Low problem in a Scion?

- It is important to address the issue promptly to prevent further damage to the vehicle's electrical system and components.

8. Can a DIY enthusiast fix the C120B code issue in a Scion?

- Depending on the underlying cause, some DIY enthusiasts with experience in automotive repair may be able to address the C120B code, especially if it involves tasks like replacing a battery or checking connections.

9. Will resetting the OBDII system clear the C120B code in a Scion?

- Resetting the OBDII system may temporarily clear the code, but it is essential to diagnose and fix the underlying issue to prevent the code from reappearing.

10. How much does it typically cost to repair the Ignition Supply Voltage Low problem in a Scion?

- The cost of repairing the C120B code can vary depending on the specific cause, but it may range from a simple battery replacement to more complex repairs involving the alternator or electrical system, potentially costing a few hundred dollars.