Engine-Codes.com
Engine-Codes – GMC – P18B8 2014 GMC Sierra

P18B8 2014 GMC Sierra Code - Internal Mode Switch 'P' Circuit Shorted

Quick Answer

The diagnostic trouble code P18B8 for a 2014 GMC Sierra indicates that there is a short circuit in the internal mode switch 'P' circuit. Common causes include Short circuit in the internal mode switch 'P' circuit, Faulty internal mode switch, Damaged wiring or connectors. 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
P18B8 2014 GMC Sierra indicates Internal Mode Switch 'P' Circuit Shorted.
Common causes
Common causes include Short circuit in the internal mode switch 'P' circuit, Faulty internal mode switch, Damaged wiring or connectors.
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 Sep 17, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P18B8 2014 GMC Sierra Description

The diagnostic trouble code P18B8 for a 2014 GMC Sierra indicates that there is a short circuit in the internal mode switch 'P' circuit. The internal mode switch is a component within the transmission control module that helps to determine the gear selection and mode of operation for the transmission. When this circuit is shorted, it can lead to issues with the transmission's performance and operation.

OBDII Code P18B8 2014 GMC Sierra - Internal Mode Switch 'P' Circuit Shorted
P18B8 2014 GMC Sierra Code - Internal Mode Switch 'P' Circuit Shorted

Common Causes of P18B8 2014 GMC Sierra

  1. Short circuit in the internal mode switch 'P' circuit
  2. Faulty internal mode switch
  3. Damaged wiring or connectors
  4. Issues with the transmission control module
  5. Water or corrosion damage to electrical components

Symptoms of P18B8 2014 GMC Sierra

  1. Erratic shifting behavior
  2. Harsh shifting between gears
  3. Transmission getting stuck in a specific gear
  4. Transmission slipping
  5. Illumination of the check engine light

How to Fix P18B8 2014 GMC Sierra

  1. Diagnose the issue using a scan tool to confirm the P18B8 code and identify the specific cause of the problem.
  2. Inspect the internal mode switch, wiring, and connectors for any visible damage or signs of wear.
  3. Replace the internal mode switch if it is found to be faulty.
  4. Repair or replace any damaged wiring or connectors.
  5. Clear the trouble code and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P18B8 2014 GMC Sierra

The typical repair costs for addressing a P18B8 code in a 2014 GMC Sierra can range from $200 to $500, depending on the exact cause of the issue and the cost of parts and labor in your area. It's important to note that diagnosis time and labor rates can vary, so it's advisable to check with local auto repair shops for a more accurate estimate. Keep in mind that rates may be higher at dealerships or in metropolitan areas, while independent shops may offer more competitive pricing.

Need more information about the P18B8 2014 GMC Sierra code?

Need more information on how to fix the P18B8 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P18B8 2014 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 P18B8 2014 GMC Sierra Code

1. What does the OBDII code P18B8 mean on a 2014 GMC Sierra?

The code P18B8 indicates an issue with the Internal Mode Switch 'P' Circuit, specifically a shorted condition.

2. What are the common symptoms of the P18B8 code?

Symptoms may include the inability to shift into or out of park, the check engine light turning on, or erratic transmission behavior.

3. What causes the P18B8 code to appear?

This code is often caused by a short in the Internal Mode Switch 'P' Circuit, damaged wiring or connectors, or a faulty internal mode switch in the transmission.

4. Can driving with the P18B8 code damage my 2014 GMC Sierra?

Yes, driving with this code can lead to further transmission or electrical issues if not addressed promptly.

5. How do I diagnose the P18B8 code?

Diagnosis involves inspecting the wiring and connectors for damage, testing the internal mode switch for proper operation, and checking for any shorts in the circuit.

6. Is replacing the internal mode switch the only fix for P18B8?

Not always; it depends on the root cause. Repairs could involve fixing a wiring short or replacing damaged connectors instead of the switch itself.

7. What tools are needed to troubleshoot the P18B8 code?

A multimeter, wiring diagrams, and an OBDII scanner are essential for diagnosing this code.

8. How much does it cost to fix the P18B8 code on a GMC Sierra?

Repair costs vary but may range from $100 to $500, depending on whether it's a wiring repair or a replacement of the internal mode switch.

9. Can I reset the P18B8 code without repairs?

You can clear the code with an OBDII scanner, but it will likely return if the underlying issue is not resolved.

10. Is the P18B8 code common in the 2014 GMC Sierra?

While not extremely common, this code can occur in GMC Sierras due to wear and tear or electrical issues in the transmission system.

Discuss the causes and fixes for P18B8 2014 GMC Sierra OBDII Code

Submit a New Comment

Code P18B8 2014 GMC Sierra comments

No comments found for this page.