C1118 2018 GMC Sierra Code - Trailer Brake Control Sensitivity Switch Circuit Malfunction
Quick Answer
The trailer brake control system has a control panel with the trailer gain and manual apply switches. Common causes include Faulty Trailer Brake Control Switch, Trailer Brake Control Switch harness is open or shorted, Trailer Brake Control 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
- C1118 2018 GMC Sierra indicates Trailer Brake Control Sensitivity Switch Circuit Malfunction.
- Common causes
- Common causes include Faulty Trailer Brake Control Switch, Trailer Brake Control Switch harness is open or shorted, Trailer Brake Control 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 C1118 2018 GMC Sierra Description
What are the Possible Causes of the DTC C1118 2018 GMC Sierra?
- Faulty Trailer Brake Control Switch
- Trailer Brake Control Switch harness is open or shorted
- Trailer Brake Control Switch circuit poor electrical connection
- Faulty Chassis Control Module-Auxiliary
How to Fix the DTC C1118 2018 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 C1118 2018 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.
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Frequently Asked Questions about C1118 2018 GMC Sierra Code
1. What does the OBDII code C1118 mean on a 2018 GMC Sierra?
C1118 indicates a malfunction in the Trailer Brake Control Sensitivity Switch Circuit, which affects the proper operation of the trailer brake system.
2. What are the symptoms of a C1118 code on a 2018 GMC Sierra?
Common symptoms include the trailer brakes not functioning properly, a warning light on the dashboard, and possible error messages related to the trailer brake system.
3. What causes the C1118 code to appear on a 2018 GMC Sierra?
The most common causes include a faulty trailer brake control sensitivity switch, damaged wiring or connectors in the circuit, or a malfunctioning trailer brake control module.
4. Can I still drive my 2018 GMC Sierra with a C1118 code?
You can still drive the truck, but towing a trailer without properly functioning trailer brakes is unsafe and not recommended.
5. How do I diagnose the C1118 code on my GMC Sierra?
Start by visually inspecting the trailer brake control sensitivity switch, wiring, and connectors for damage. Use a multimeter to test for continuity and voltage in the circuit if necessary.
6. How do I fix a C1118 code on a 2018 GMC Sierra?
Repairs may involve replacing the trailer brake control sensitivity switch, repairing damaged wiring, or recalibrating or replacing the trailer brake control module.
7. Is the C1118 code specific to trailer brake issues?
Yes, this code specifically relates to a malfunction in the trailer brake control sensitivity switch circuit.
8. How much does it typically cost to fix a C1118 code on a 2018 GMC Sierra?
Repair costs can vary, but replacing the trailer brake control sensitivity switch or repairing wiring may cost between $100 and $300 depending on labor rates and parts availability.
9. Can a faulty trailer brake control module trigger a C1118 code?
Yes, a malfunctioning trailer brake control module can cause the C1118 code if it fails to communicate properly with the sensitivity switch.
10. Will clearing the C1118 code solve the issue permanently?
Clearing the code may temporarily remove the warning, but the underlying issue must be resolved to prevent the code from returning.
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