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Engine-Codes – Generic – B142A

B142A Code - Ignition Voltage

Quick Answer

The diagnostic code B142A indicates an issue related to the ignition voltage supplied to the Airbag Diagnosis Sensor Unit, which is critical for the proper functioning of the vehicle's airbag system. Common causes include Faulty Airbag Diagnosis Sensor UnitOpen or shorted wiring harness connected to the Airbag Diagnosis Sensor UnitPoor electrical connections within the Airbag Diagnosis Sensor Unit circuitFaulty ignition switch affecting voltage supplyElectrical interference from other components or systems in the vehicle. 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
B142A indicates Ignition Voltage.
Common causes
Common causes include Faulty Airbag Diagnosis Sensor UnitOpen or shorted wiring harness connected to the Airbag Diagnosis Sensor UnitPoor electrical connections within the Airbag Diagnosis Sensor Unit circuitFaulty ignition switch affecting voltage supplyElectrical interference from other components or systems in the vehicle.
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.
What is this?
Table of contents Created and updated by William Orellana on Nov 10, 2025
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Code B142A Description

The diagnostic code B142A indicates an issue related to the ignition voltage supplied to the Airbag Diagnosis Sensor Unit, which is critical for the proper functioning of the vehicle's airbag system. The Airbag Diagnosis Sensor Unit, also referred to as the Airbag Control Module or Electronic Crash Unit, plays a vital role in monitoring the vehicle's safety systems. It continuously assesses data from various collision sensors and determines whether the conditions warrant airbag deployment in the event of a crash. When the ignition is turned to the ON position, the unit receives the necessary voltage to operate. If the voltage is too low or too high, it can trigger the B142A code, indicating a malfunction in the ignition voltage supply.
OBDII Code B142A - Ignition Voltage
B142A Code - Ignition Voltage

Common Causes of B142A

  1. Faulty Airbag Diagnosis Sensor Unit
  2. Open or shorted wiring harness connected to the Airbag Diagnosis Sensor Unit
  3. Poor electrical connections within the Airbag Diagnosis Sensor Unit circuit
  4. Faulty ignition switch affecting voltage supply
  5. Electrical interference from other components or systems in the vehicle

Symptoms of B142A

  1. Air Bag Warning Light ON
  2. Engine Light ON (or Service Engine Soon Warning Light)
  3. Intermittent airbag deployment issues
  4. Inconsistent performance of other electrical systems
  5. Diagnostic trouble codes related to airbag system stored in the ECU

How to Fix B142A

  1. Perform a visual inspection of the Airbag Diagnosis Sensor Unit and its wiring harness for any signs of damage or corrosion.
  2. Test the voltage supply to the Airbag Diagnosis Sensor Unit with a multimeter to ensure it is within the manufacturer's specified range.
  3. If the voltage is outside the acceptable range, check the ignition switch and associated wiring for faults.
  4. Replace any damaged wiring or connectors, and if necessary, replace the Airbag Diagnosis Sensor Unit.
  5. Clear the diagnostic trouble codes and perform a system reset to ensure proper functionality of the airbag system.

Cost to Fix B142A

The cost to diagnose and repair the B142A code can vary significantly based on the specific issue identified. Typical parts and labor costs range from $150 to $600, depending on whether the Airbag Diagnosis Sensor Unit needs replacement or if wiring repairs are necessary. Labor rates typically range from $80 to $150 per hour, with dealerships generally charging more than independent shops. The total cost may also be influenced by the vehicle's make and model, as well as the local labor market.

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Code B142A Information for Specific Makes

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

  • Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
  • Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
  • Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
  • Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.

Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

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 B142A Code

1. What are the common symptoms of OBDII code B142A (Ignition Voltage)?

- Common symptoms of code B142A include issues with starting the vehicle, intermittent stalling, and a non-responsive ignition system.

2. What are the possible causes of OBDII code B142A?

- Possible causes of code B142A include a faulty ignition switch, damaged wiring or connectors in the ignition system, or a failing ignition control module.

3. How can I diagnose OBDII code B142A?

- To diagnose code B142A, it is recommended to use a diagnostic scan tool to retrieve the specific fault code. Additionally, inspecting the ignition system components for visible damage or wear can help identify the issue.

4. Can a DIY enthusiast repair OBDII code B142A at home?

- Repairing code B142A may require advanced automotive knowledge and tools. DIY enthusiasts can attempt to repair this code at home by carefully inspecting and potentially replacing the ignition system components themselves.

5. What are some repair tips for fixing OBDII code B142A?

- Repair tips for code B142A include checking and replacing the ignition switch, inspecting and repairing damaged wiring or connectors, and ensuring proper grounding in the ignition system.

6. Is it safe to drive with OBDII code B142A present?

- It is not recommended to drive with code B142A present, as it can lead to potential issues with starting the vehicle or unexpected stalling while driving.

7. Can a low battery voltage trigger OBDII code B142A?

- Yes, a low battery voltage can potentially trigger code B142A as it may affect the proper functioning of the ignition system components.

8. How long does it typically take to repair OBDII code B142A?

- The repair time for code B142A can vary depending on the exact cause of the issue and the availability of replacement parts. It may take a few hours to a full day to diagnose and repair this code.

9. Will resetting the OBDII system clear code B142A?

- Resetting the OBDII system may temporarily clear code B142A, but if the underlying issue is not addressed, the code is likely to reappear once the problem resurfaces.

10. Can extreme weather conditions impact OBDII code B142A?

- Extreme weather conditions, such as extreme cold or heat, can potentially affect the performance of the ignition system components and contribute to triggering code B142A.

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