AutoCodes – GMC – P18BB 2014 GMC Sierra

P18BB 2014 GMC Sierra Code - Internal Mode Switch 'B' Circuit Stuck Off Invalid Voltage Range

Quick Answer

The internal mode switch indicates the Transmission Control Module (TCM) which gear position the vehicle operator has selected. Common causes include Faulty Transmission Internal Mode Switch, Transmission Internal Mode Switch harness is open or shorted, Transmission Internal Mode 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: P18BB 2014 GMC Sierra indicates Internal Mode Switch 'B' Circuit Stuck Off Invalid Voltage Range.
Common causes: Common causes include Faulty Transmission Internal Mode Switch, Transmission Internal Mode Switch harness is open or shorted, Transmission Internal Mode 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 143

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 Mar 23, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P18BB 2014 GMC Sierra Description

The internal mode switch indicates the Transmission Control Module (TCM) which gear position the vehicle operator has selected. The internal mode switch consists of 5 separate hall effect switches. Each hall effect switch is supplied with a 9 V reference circuit and a signal circuit from the TCM. Each signal circuit for each gear selector position will have either a voltage reading of 0.70–0.96 V indicating On or 1.68–2.38 V indicating Off. The voltage values on each internal mode switch circuit will change and are dependent on the position of the gear selector. The state of each internal mode switch A/B/C/P/S signal circuit is displayed on the scan tool. The Diagnostic Trouble Code (DTC) will be set when the TCM has detected the internal mode switch B signal circuit has an invalid voltage range of 1.68 – 2.38 V for 2.7 s.

OBDII Code P18BB 2014 GMC Sierra - Internal Mode Switch 'B' Circuit Stuck Off Invalid Voltage Range - AutoCodes.com — P18BB 2014 GMC Sierra Code - Internal Mode Switch 'B' Circuit Stuck Off Invalid Voltage Range

What does this mean?

What are the Possible Causes of the DTC P18BB 2014 GMC Sierra?

Faulty Transmission Internal Mode Switch
Transmission Internal Mode Switch harness is open or shorted
Transmission Internal Mode Switch circuit poor electrical connection
Faulty Transmission Control Module (TCM)

How to Fix the DTC P18BB 2014 GMC Sierra?

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 P18BB 2014 GMC Sierra 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 P18BB 2014 GMC Sierra code?

Need more information on how to fix the P18BB 2014 GMC Sierra code? Get Access to Factory Service Manuals

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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 P18BB 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P18BB in a 2014 GMC Sierra?

The common symptoms of OBDII code P18BB in a 2014 GMC Sierra include issues with shifting gears, sudden loss of power, and dashboard warning lights related to the transmission system.

2. What does the OBDII code P18BB 'Internal Mode Switch 'B' Circuit Stuck Off Invalid Voltage Range' mean for a 2014 GMC Sierra?

The OBDII code P18BB indicates that there is an issue with the internal mode switch 'B' circuit in the transmission system of a 2014 GMC Sierra, specifically related to an invalid voltage range.

3. What are the possible causes of OBDII code P18BB in a 2014 GMC Sierra?

Possible causes of OBDII code P18BB in a 2014 GMC Sierra include a faulty internal mode switch, damaged wiring or connectors in the circuit, or issues with the transmission control module.

4. How can I diagnose the OBDII code P18BB in my 2014 GMC Sierra?

Diagnosing OBDII code P18BB in a 2014 GMC Sierra typically involves using a scan tool to retrieve the code, checking the internal mode switch and its circuit for faults, and inspecting the wiring and connectors for any damage or loose connections.

5. Can I continue driving my 2014 GMC Sierra with OBDII code P18BB?

It is not recommended to continue driving a 2014 GMC Sierra with OBDII code P18BB, as it can lead to further damage to the transmission system and potentially unsafe driving conditions.

6. How can I repair OBDII code P18BB in my 2014 GMC Sierra?

To repair OBDII code P18BB in a 2014 GMC Sierra, you may need to replace the internal mode switch, repair any damaged wiring or connectors, or reprogram the transmission control module as necessary.

7. Are there any DIY tips for fixing OBDII code P18BB in a 2014 GMC Sierra?

While some basic inspections and checks can be done by DIY enthusiasts, it is recommended to consult a professional mechanic for diagnosing and repairing OBDII code P18BB in a 2014 GMC Sierra due to the complexity of transmission systems.

8. How much does it cost to fix OBDII code P18BB in a 2014 GMC Sierra?

The cost of fixing OBDII code P18BB in a 2014 GMC Sierra can vary depending on the specific cause of the issue, parts needed for repair, and labor costs. It is advisable to obtain quotes from reputable repair shops for an accurate estimate.

9. Can resetting the OBDII codes clear P18BB in a 2014 GMC Sierra?

Resetting the OBDII codes may temporarily clear the P18BB code in a 2014 GMC Sierra, but if the underlying issue causing the code is not addressed, it is likely to reappear. It is important to diagnose and fix the root cause of the problem.

10. Is OBDII code P18BB a common issue in 2014 GMC Sierra vehicles?

While OBDII code P18BB may not be as common as some other codes, it can still occur in 2014 GMC Sierra vehicles due to various factors such as wear and tear, electrical issues, or component failures within the transmission system.