AutoCodes – GMC – P18B7 2014 GMC Sierra

P18B7 2014 GMC Sierra Code - Internal Mode Switch 'C' Circuit Shorted

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: P18B7 2014 GMC Sierra indicates Internal Mode Switch 'C' Circuit Shorted.
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 168

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 P18B7 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 C signal circuit voltage is between 0.966–1.68 V, for 1.75 s.

OBDII Code P18B7 2014 GMC Sierra - Internal Mode Switch 'C' Circuit Shorted - AutoCodes.com — P18B7 2014 GMC Sierra Code - Internal Mode Switch 'C' Circuit Shorted

What does this mean?

What are the Possible Causes of the DTC P18B7 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 P18B7 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 P18B7 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 P18B7 2014 GMC Sierra code?

Need more information on how to fix the P18B7 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 P18B7 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P18B7 in a 2014 GMC Sierra?

The common symptoms of OBDII code P18B7 in a 2014 GMC Sierra include issues with shifting gears, the inability to shift out of park, and the malfunction indicator light (MIL) illuminating on the dashboard.

2. What does the OBDII code P18B7 'Internal Mode Switch C Circuit Shorted' mean for a 2014 GMC Sierra?

The OBDII code P18B7 indicates that there is a short circuit in the 'C' circuit of the Internal Mode Switch in a 2014 GMC Sierra. This switch is responsible for providing input to the transmission control module regarding the gear shift position.

3. What are the possible causes of OBDII code P18B7 in a 2014 GMC Sierra?

Possible causes of OBDII code P18B7 in a 2014 GMC Sierra include a faulty internal mode switch, damaged wiring or connectors in the circuit, or a malfunctioning transmission control module.

4. How can I diagnose OBDII code P18B7 in my 2014 GMC Sierra?

Diagnosing OBDII code P18B7 in a 2014 GMC Sierra involves using a scan tool to retrieve the specific fault code, checking the internal mode switch for proper operation, inspecting the wiring and connectors for any damage, and testing the transmission control module.

5. Can I continue driving my 2014 GMC Sierra with OBDII code P18B7?

It is not recommended to continue driving your 2014 GMC Sierra with OBDII code P18B7, as it can lead to potential transmission issues and further damage. It is advisable to address the underlying problem promptly.

6. How can I repair OBDII code P18B7 in my 2014 GMC Sierra?

Repairing OBDII code P18B7 in a 2014 GMC Sierra may involve replacing the internal mode switch, repairing or replacing damaged wiring or connectors, or reprogramming the transmission control module. It is recommended to consult a professional mechanic for proper diagnosis and repair.

7. Is OBDII code P18B7 a serious issue in a 2014 GMC Sierra?

OBDII code P18B7 should be taken seriously in a 2014 GMC Sierra as it can cause transmission-related problems and affect the vehicle's drivability. Addressing this issue promptly can help prevent further damage and ensure safe operation of the vehicle.

8. How much does it cost to fix OBDII code P18B7 in a 2014 GMC Sierra?

The cost to fix OBDII code P18B7 in a 2014 GMC Sierra can vary depending on the exact cause of the issue, parts needed for repair, and labor costs. It is advisable to obtain quotes from different repair shops to determine the total repair cost.

9. Can I reset OBDII code P18B7 in my 2014 GMC Sierra without repairing the issue?

While you can clear the fault code and reset the MIL in your 2014 GMC Sierra, it is not recommended to do so without addressing the underlying problem. Resetting the code without fixing the issue may lead to recurring problems and potential safety risks.

10. How can I prevent OBDII code P18B7 from occurring in my 2014 GMC Sierra in the future?

To prevent OBDII code P18B7 from occurring in your 2014 GMC Sierra in the future, it is essential to perform regular vehicle maintenance, address any transmission-related issues promptly, and avoid rough handling of the gear shifter. Routine inspections and servicing can help maintain the internal mode switch and related components in good condition.