Engine-CodesGMC – C1291 GMC

C1291 GMC Code - Open Brake Lamp Switch Contacts During Deceleration

Quick Answer

The C1291 GMC code indicates that there is an open circuit detected in the brake lamp switch contacts during deceleration. Common causes include Faulty brake lamp switch, Loose or corroded electrical connections related to the brake lamp switch, Damaged or worn-out wiring harness leading to the brake lamp switch. 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
C1291 GMC indicates Open Brake Lamp Switch Contacts During Deceleration.
Common causes
Common causes include Faulty brake lamp switch, Loose or corroded electrical connections related to the brake lamp switch, Damaged or worn-out wiring harness leading to the brake lamp switch.
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.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code C1291 GMC Description

The C1291 GMC code indicates that there is an open circuit detected in the brake lamp switch contacts during deceleration. This means that the brake lamp switch, which is responsible for activating the brake lights when the brake pedal is pressed, is not functioning properly during deceleration. When this issue occurs, the vehicle's braking system may not operate as intended, potentially leading to safety concerns such as delayed brake light activation or failure to activate the brake lights at all. This can impact the ability of other drivers to react to your vehicle's braking actions, increasing the risk of rear-end collisions.

OBDII Code C1291 GMC - Open Brake Lamp Switch Contacts During Deceleration
C1291 GMC Code - Open Brake Lamp Switch Contacts During Deceleration

Common Causes of C1291 GMC

  1. Faulty brake lamp switch
  2. Loose or corroded electrical connections related to the brake lamp switch
  3. Damaged or worn-out wiring harness leading to the brake lamp switch
  4. Issues with the brake pedal position sensor
  5. Electronic control module (ECM) malfunction

Symptoms of C1291 GMC

  1. Brake lights not illuminating during deceleration
  2. Delayed response of brake lights when the brake pedal is pressed
  3. Warning light on the dashboard indicating a brake lamp switch malfunction
  4. Other drivers signaling that your brake lights are not working properly

How to Fix C1291 GMC

  1. Begin by locating the brake lamp switch, typically located near the brake pedal under the dashboard.
  2. Inspect the electrical connections and wiring harness connected to the brake lamp switch for any signs of damage, corrosion, or looseness.
  3. Test the brake lamp switch using a multimeter to determine if it is functioning correctly.
  4. If the brake lamp switch is found to be faulty, replace it with a new one following the manufacturer's guidelines.
  5. Clear the diagnostic trouble codes from the vehicle's computer using a scan tool and test the brake lights to ensure they are functioning properly.

Cost to Fix C1291 GMC

The cost of repairing an open brake lamp switch contacts during deceleration issue can vary depending on the extent of the damage, the cost of the replacement parts, and the labor rates of the auto repair shop. Typically, the cost of replacing a brake lamp switch can range from $50 to $150, while the labor cost can be between $80 and $150 per hour. In total, the repair cost for this issue may range from $150 to $300, but it's advisable to get a personalized quote from a local auto repair shop to get a more accurate estimate. Keep in mind that rates can vary based on location, vehicle make and model, and other factors.

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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 C1291 GMC Code

What does the OBDII code C1291 mean for a GMC vehicle?

C1291 indicates that the brake lamp switch contacts are open during deceleration, which can affect the vehicle's braking system and stability control.

What symptoms might indicate the presence of code C1291?

Common symptoms include the brake warning light being illuminated on the dashboard, issues with the brake lights not functioning properly, and possible stability control system warnings.

What could cause the C1291 code to trigger?

Causes may include a faulty brake lamp switch, wiring issues related to the brake switch, or problems within the vehicle's electronic control module (ECM).

How can I diagnose the issue related to code C1291?

Start by inspecting the brake lamp switch and its wiring for any damage or disconnections. Use a multimeter to test the switch for proper operation and continuity.

What repairs are typically needed to fix code C1291?

Repair options may include replacing the brake lamp switch, repairing any damaged wiring, or addressing any underlying issues with the vehicle’s ECM.

Can I drive my GMC with the C1291 code?

While it may be possible to drive the vehicle, it is not recommended due to potential braking issues and the risk of stability control malfunction.

How can I reset the C1291 code after repairs?

After addressing the issue, you can reset the code using an OBDII scanner. Disconnecting the battery for a few minutes may also clear the code, but this can reset other settings.

Will the brake lights function properly if the C1291 code is present?

Not necessarily; the code indicates a problem with the brake lamp switch, which may result in brake lights not functioning as intended.

What is the importance of addressing the C1291 code promptly?

Ignoring the C1291 code can lead to unsafe driving conditions, as it may impact braking performance and vehicle stability, potentially resulting in accidents.

Discuss the causes and fixes for C1291 GMC OBDII Code

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