B108B Code - Start Button Circuit 'A'
Quick Answer
Conventional Ignition Switch: The ignition switch is a multiple position rotary switch that is controlled by a lock cylinder and a key. Common causes include Faulty Start Button Switch, Start Button Switch harness is open or shorted, Start Button Switch circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
- What it means
- B108B indicates Start Button Circuit 'A'.
- Common causes
- Common causes include Faulty Start Button Switch, Start Button Switch harness is open or shorted, Start Button Switch circuit poor electrical connection.
- Severity
- Moderate - service should be scheduled soon.
- Can I drive?
- The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Code B108B Description
The ignition switch is a multiple position rotary switch that is controlled by a lock cylinder and a key. The ignition switch provides voltage to the ACC, ON, or START-designated circuits depending on the position it is placed. The Body Control Module (BCM) calculates the positions based on the voltage received from the ACC and ON-designated circuits.
The key removal inhibit solenoid (also known as the key release interlock actuator) is an electronically controlled solenoid that prevents the ignition lock cylinder from being turned to the OFF position unless the gear selector lever is in the PARK position. The key removal inhibit solenoid is part of the ignition switch.
Push Button Ignition Switch:
The push button ignition switch is used instead of a conventional ignition switch to achieve the various ignition modes. The push button ignition switch is a momentary dual contact switch. Both sets of contacts are normally open and receive the voltage at all times. When the START/STOP button is pressed, the voltage is sent to the BCM, the RFA module, and the PCM to indicate a button press.
The ignition switch has a LED for switch illumination when the backlighting is activated.
What are the Possible Causes of the DTC B108B?
- Faulty Start Button Switch
- Start Button Switch harness is open or shorted
- Start Button Switch circuit poor electrical connection
- Faulty Body Control Module (BCM)
How to Fix the DTC B108B?
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.
Code Tech Notes
B108B:24 Start Button Circuit 'A' Signal Stuck High
B108B:2F Start Button Circuit 'A' Signal Erratic
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B108B 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 Makes
- B108B Ford — Start Button Circuit 'A'
- B108B Lincoln — Start Button Circuit 'A'
- B108B Mercury — Start Button Circuit 'A'
Frequently Asked Questions about B108B Code
1. What are the common symptoms of OBDII code B108B (Start Button Circuit 'A')?
- Common symptoms include the inability to start the vehicle using the start button, intermittent starting issues, and the engine not turning over.
2. What are the possible causes of OBDII code B108B?
- Possible causes of this code include a faulty start button, damaged wiring or connectors in the start button circuit, or a problem with the start button control module.
3. How can I diagnose the issue related to OBDII code B108B?
- A thorough inspection of the start button, wiring, and connectors is recommended. Testing the start button circuit for continuity and checking for any visible damage can help pinpoint the issue.
4. Can I continue driving my vehicle with OBDII code B108B present?
- It is not advisable to continue driving the vehicle with this code present, as it can lead to potential starting issues and may leave you stranded.
5. How can I repair OBDII code B108B?
- Repairing this code typically involves replacing the faulty start button, repairing or replacing damaged wiring or connectors, or addressing any issues with the start button control module.
6. Are there any DIY tips for fixing OBDII code B108B?
- DIY tips include carefully inspecting the start button and surrounding wiring for any visible damage, ensuring all connections are secure, and consulting the vehicle's repair manual for specific troubleshooting steps.
7. Can a malfunctioning battery cause OBDII code B108B to appear?
- Yes, a weak or failing battery can sometimes trigger this code due to insufficient power reaching the start button circuit. It's recommended to check the battery's condition as part of the diagnosis.
8. Is it possible for a loose connection to trigger OBDII code B108B?
- Yes, a loose or poor connection in the start button circuit can cause this code to appear. It's important to check all connections for tightness and corrosion during diagnosis.
9. Will resetting the OBDII code B108B make it go away permanently?
- Resetting the code may temporarily clear it, but if the underlying issue is not addressed, the code is likely to reappear. It's crucial to diagnose and repair the root cause of the problem.
10. How long does it typically take to repair OBDII code B108B?
- The repair time can vary depending on the exact cause of the issue and the availability of parts. In general, it may take a few hours to a day to diagnose and repair this code effectively.
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