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B142A Nissan 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 Nissan 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 Nissan 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 Nissan - Ignition Voltage
B142A Nissan Code - Ignition Voltage

Common Causes of B142A Nissan

  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 Nissan

  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 Nissan

  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 Nissan

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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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 Nissan Code

1. What are the common symptoms of OBDII code B142A in a Nissan related to ignition voltage?

The common symptoms include difficulty starting the vehicle, intermittent stalling, and possible issues with the vehicle's electrical components.

2. What are some possible causes of OBDII code B142A in a Nissan?

Possible causes include a faulty ignition switch, wiring issues in the ignition system, a damaged ignition coil, or problems with the engine control module.

3. How can I diagnose the OBDII code B142A in my Nissan related to ignition voltage?

You can diagnose the code by using an OBDII scanner to retrieve the specific fault code, checking the ignition system components for any visible damage, and testing the ignition switch and related wiring for proper voltage.

4. What are some repair tips for fixing OBDII code B142A in a Nissan?

Repair tips include replacing a faulty ignition switch, repairing any damaged wiring in the ignition system, replacing a malfunctioning ignition coil, or reprogramming the engine control module if necessary.

5. Can OBDII code B142A in a Nissan cause any long-term damage if left unrepaired?

Continued driving with this code can potentially cause damage to other electrical components in the vehicle and may lead to more serious issues with the vehicle's performance and reliability.

6. How urgent is it to address OBDII code B142A in a Nissan related to ignition voltage?

It is recommended to address the issue promptly to prevent any further damage and ensure the vehicle's safe operation. Ignition-related problems can affect the overall performance of the vehicle.

7. Will resetting the OBDII code B142A in a Nissan make the issue go away permanently?

Simply resetting the code without addressing the underlying cause will not permanently resolve the issue. It is essential to diagnose and repair the root cause of the problem to prevent it from recurring.

8. Are there any preventive measures to avoid encountering OBDII code B142A in a Nissan related to ignition voltage?

Regularly maintaining the vehicle's ignition system, checking for any signs of wear or damage in the components, and addressing any issues promptly can help prevent this code from appearing.

9. Can extreme weather conditions impact the likelihood of OBDII code B142A in a Nissan occurring?

Extreme weather conditions, such as extreme heat or cold, can potentially exacerbate existing issues in the ignition system and increase the likelihood of encountering OBDII code B142A.

10. Is it possible to drive a Nissan with OBDII code B142A related to ignition voltage?

While it may be possible to drive the vehicle with this code present, it is not recommended as it can lead to performance issues, potential stalling, and further damage to the vehicle if left unresolved.

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