P18C0 2014 GMC Sierra Code - Internal Mode Switch 'B' Circuit Stuck On 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
- P18C0 2014 GMC Sierra indicates Internal Mode Switch 'B' Circuit Stuck On 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.
Code P18C0 2014 GMC Sierra Description
What are the Possible Causes of the DTC P18C0 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 P18C0 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 P18C0 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 P18C0 2014 GMC Sierra code?
Need more information on how to fix the P18C0 2014 GMC Sierra code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P18C0 2014 GMC Sierra code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P18C0 2014 GMC Sierra Code
1. What does the OBDII code P18C0 mean on a 2014 GMC Sierra?
P18C0 indicates an issue with the Internal Mode Switch 'B' Circuit, where the voltage signal is stuck in an invalid range, potentially affecting the transmission's ability to determine gear position.
2. What are the common symptoms of the P18C0 code on a 2014 GMC Sierra?
Symptoms may include the check engine light turning on, erratic shifting, the transmission stuck in a single gear, or difficulty selecting gears.
3. What causes the P18C0 code to appear on a 2014 GMC Sierra?
Common causes include a faulty internal mode switch, damaged wiring or connectors in the circuit, transmission control module (TCM) issues, or corrosion affecting the electrical connection.
4. Can I drive my 2014 GMC Sierra with the P18C0 code?
Driving with this code is not recommended, as it can lead to unsafe shifting behavior or damage the transmission over time if the issue is not resolved.
5. How is the P18C0 code diagnosed?
A mechanic will use a scan tool to confirm the code, inspect the internal mode switch and wiring for damage or corrosion, and test the voltage and continuity of the circuit.
6. How do you fix the P18C0 code on a 2014 GMC Sierra?
Repairs may involve replacing the internal mode switch, repairing or replacing damaged wiring or connectors, cleaning corroded connections, or reprogramming the TCM if necessary.
7. Is the P18C0 code related to the transmission in the 2014 GMC Sierra?
Yes, the code directly relates to the internal mode switch, which is a critical component in the transmission system responsible for detecting gear position.
8. How much does it cost to fix the P18C0 code on a 2014 GMC Sierra?
Repair costs vary depending on the issue, but replacing the internal mode switch typically costs $200–$400, including parts and labor. Wiring repairs may vary based on the extent of the damage.
9. Can a failing battery cause the P18C0 code in a 2014 GMC Sierra?
While uncommon, a failing battery or low voltage can sometimes cause electrical issues that trigger this code. It's worth checking the battery and charging system as part of the diagnosis.
10. What happens if I ignore the P18C0 code on my 2014 GMC Sierra?
Ignoring this code can lead to worsening transmission performance, potential safety risks, and more expensive repairs if further damage occurs.
Discuss the causes and fixes for P18C0 2014 GMC Sierra OBDII Code
Code P18C0 2014 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.
