P18B8 2015 GMC Sierra Code - Internal Mode Switch 'P' Circuit Shorted
Quick Answer
The diagnostic trouble code P18B8 for the 2015 GMC Sierra indicates an issue with the Internal Mode Switch 'P' Circuit being shorted. Common causes include Faulty Internal Mode Switch, Damaged or corroded wiring in the 'P' circuit, Loose or poor connections in the circuit. 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 2015 GMC Sierra indicates Internal Mode Switch 'P' Circuit Shorted.
- Common causes
- Common causes include Faulty Internal Mode Switch, Damaged or corroded wiring in the 'P' circuit, Loose or poor connections in the circuit.
- 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.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
Code P18B8 2015 GMC Sierra Description
The diagnostic trouble code P18B8 for the 2015 GMC Sierra indicates an issue with the Internal Mode Switch 'P' Circuit being shorted. The Internal Mode Switch (IMS) is a component within the transmission that helps the vehicle's computer system determine the gear position and the driver's selected transmission mode (Park, Reverse, Neutral, Drive, etc.). When the 'P' circuit of the IMS is shorted, it means that there is an electrical problem causing the circuit to have a lower resistance than normal, which can disrupt the communication between the transmission and the vehicle's computer.
Common Causes of P18B8 2015 GMC Sierra
- Faulty Internal Mode Switch
- Damaged or corroded wiring in the 'P' circuit
- Loose or poor connections in the circuit
- Issues with the transmission control module
- Electrical short circuits in the system
Symptoms of P18B8 2015 GMC Sierra
- Harsh shifting between gears
- Inaccurate gear position display on the dashboard
- Difficulty engaging specific gears
- Transmission slipping or not engaging at all
How to Fix P18B8 2015 GMC Sierra
- Diagnose the issue by using a scan tool to retrieve the trouble code and inspect the Internal Mode Switch and related wiring for any visible damage.
- Replace the Internal Mode Switch if it is found to be faulty, ensuring the new component is properly installed and calibrated.
- Repair or replace any damaged wiring or connectors in the 'P' circuit to restore proper electrical connections.
- Clear the trouble code from the vehicle's computer and test drive the vehicle to ensure the issue has been resolved.
- Perform a transmission relearn procedure to recalibrate the transmission control module and ensure proper operation.
Cost to Fix P18B8 2015 GMC Sierra
The typical repair costs for addressing a P18B8 code on a 2015 GMC Sierra can range from $200 to $500, including parts and labor. However, it's important to note that specific diagnosis time and labor rates at auto repair shops can vary depending on factors such as location, vehicle make and model, and engine type. Auto repair shops commonly charge between $80 and $150 per hour for labor, with rates potentially higher at dealerships or metropolitan areas and lower at independent shops. To get a more accurate estimate, it's recommended to inquire locally.
Need more information about the P18B8 2015 GMC Sierra code?
Need more information on how to fix the P18B8 2015 GMC Sierra code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P18B8 2015 GMC Sierra code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P18B8 2015 GMC Sierra Code
What are the common symptoms of OBDII code P18B8 in a 2015 GMC Sierra?
Common symptoms of OBDII code P18B8, Internal Mode Switch 'P' Circuit Shorted, in a 2015 GMC Sierra may include issues with shifting gears, erratic transmission behavior, and possibly triggering the vehicle into "limp mode."
What are the possible causes of OBDII code P18B8 in a 2015 GMC Sierra?
Potential causes of OBDII code P18B8 in a 2015 GMC Sierra include a faulty internal mode switch, damaged wiring or connectors related to the internal mode switch, or a malfunctioning transmission control module.
How can I diagnose OBDII code P18B8 in a 2015 GMC Sierra?
Diagnosing OBDII code P18B8 in a 2015 GMC Sierra typically involves using a scan tool to retrieve the trouble code, inspecting the internal mode switch and its circuitry for any visible damage, and testing the related components for proper functionality.
Can I continue to drive my 2015 GMC Sierra with OBDII code P18B8?
It is not recommended to continue driving a 2015 GMC Sierra with OBDII code P18B8 as it can lead to further damage to the transmission system. It is advisable to address the issue promptly to avoid potential safety risks and costly repairs.
What are some repair tips for resolving OBDII code P18B8 in a 2015 GMC Sierra?
Repair tips for fixing OBDII code P18B8 in a 2015 GMC Sierra may include checking and repairing any damaged wiring or connectors, replacing the internal mode switch if necessary, and resetting the trouble codes after completing the repairs.
Is it possible to reset OBDII code P18B8 in a 2015 GMC Sierra without fixing the underlying issue?
Resetting OBDII code P18B8 in a 2015 GMC Sierra without addressing the root cause is not recommended as the problem is likely to recur. It is crucial to diagnose and repair the issue causing the trouble code to prevent further complications.
How much does it typically cost to repair OBDII code P18B8 in a 2015 GMC Sierra?
The cost of repairing OBDII code P18B8 in a 2015 GMC Sierra can vary depending on the exact cause of the issue, labor rates, and the cost of parts. It is advisable to consult a professional mechanic for an accurate estimate.
Can a DIY enthusiast fix OBDII code P18B8 in a 2015 GMC Sierra?
While some DIY enthusiasts may be able to diagnose and repair OBDII code P18B8 in a 2015 GMC Sierra, it is recommended to have the necessary knowledge, tools, and experience to work on transmission-related issues. Otherwise, consulting a professional mechanic is advised.
Discuss the causes and fixes for P18B8 2015 GMC Sierra OBDII Code
Code P18B8 2015 GMC Sierra comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.