AutoCodes – Generic – B12C5

B12C5 Code - Engine Start/Stop Switch Failure

Quick Answer

This Push Button Ignition Switch is a single pole momentary design with position indicator LEDs controlled by the Keyless access control unit. Common causes include Faulty Start/Stop Switch, Start/Stop Switch harness is open or shorted, Start/Stop Switch 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: B12C5 indicates Engine Start/Stop Switch Failure.
Common causes: Common causes include Faulty Start/Stop Switch, Start/Stop Switch harness is open or shorted, Start/Stop Switch 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 6,085

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B12C5 Description

This Push Button Ignition Switch is a single pole momentary design with position indicator LEDs controlled by the Keyless access control unit.
Once the Keyless access control unit detects the presence of a registered key fob and the brake pedal is not depressed, each time the button is pushed the Body Control Module will cycle through Accessories, On and Off modes. The Body Control Module will also illuminate the appropriate position indicator LED.
If the brake pedal is depressed, the shift lever is in Park and the button is pushed, the Keyless access control unit will start the engine.

OBDII Code B12C5 - Engine Start/Stop Switch Failure - AutoCodes.com — B12C5 Code - Engine Start/Stop Switch Failure

What does this mean?

What are the Possible Causes of the DTC B12C5?

Faulty Start/Stop Switch
Start/Stop Switch harness is open or shorted
Start/Stop Switch circuit poor electrical connection

How to Fix the DTC B12C5?

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 B12C5 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 B12C5 code?

Need more information on how to fix the B12C5 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B12C5 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B12C5 Acura — Engine Start/Stop Switch Failure
B12C5 Honda — Engine Start/Stop Switch Failure

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 B12C5 Code

1. What are the common symptoms of OBDII code B12C5 (Engine Start/Stop Switch Failure)?

The common symptoms of OBDII code B12C5 include issues with starting or stopping the engine, unresponsive engine start/stop button, and the engine not turning off properly.

2. What are the possible causes of OBDII code B12C5?

Possible causes of OBDII code B12C5 include a faulty engine start/stop switch, wiring issues, a malfunctioning control module, or a weak electrical connection.

3. How can I diagnose OBDII code B12C5?

Diagnosing OBDII code B12C5 involves using a diagnostic scanner to retrieve the fault code, inspecting the engine start/stop switch and related wiring, and testing the control module for proper function.

4. Can I continue driving with OBDII code B12C5 present?

It is not recommended to continue driving with OBDII code B12C5 present, as it can lead to potential safety issues with starting or stopping the engine.

5. How can I repair OBDII code B12C5 (Engine Start/Stop Switch Failure)?

To repair OBDII code B12C5, you may need to replace the faulty engine start/stop switch, repair any damaged wiring, reset the control module, or address any underlying electrical issues.

6. Is OBDII code B12C5 a serious issue?

OBDII code B12C5 should be addressed promptly to ensure the proper functioning of the engine start/stop system. Ignoring this code could lead to inconvenient starting or stopping issues.

7. Can a DIY enthusiast fix OBDII code B12C5 at home?

Depending on your skills and tools, DIY enthusiasts may be able to address OBDII code B12C5 by replacing the engine start/stop switch or repairing wiring issues. However, complex control module repairs may require professional assistance.

8. How much does it cost to repair OBDII code B12C5?

The cost to repair OBDII code B12C5 can vary depending on the root cause of the issue, parts needed for replacement, and labor costs. It's advisable to obtain quotes from automotive professionals for an accurate estimate.

9. Will resetting the fault code make OBDII code B12C5 disappear permanently?

Resetting the fault code associated with OBDII code B12C5 may temporarily clear the warning light, but if the underlying issue is not addressed, the code is likely to reappear, indicating ongoing engine start/stop switch failure.

10. How long does it take to repair OBDII code B12C5?

The repair time for OBDII code B12C5 can vary based on the diagnostic process, availability of parts, and the complexity of the repair. Simple fixes like replacing the switch may take a shorter time, while more intricate repairs could take longer.