AutoCodes – Generic – C1291

C1291 Code - Open Brake Lamp Switch Contacts During Deceleration

Quick Answer

The stop lamp switch signal informs the Electronic Brake Control Module (EBCM) when the brake pedal is pressed. Common causes include Faulty Brake Lamp Switch, Brake Lamp Switch harness is open or shorted, Brake Lamp 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: C1291 indicates Open Brake Lamp Switch Contacts During Deceleration.
Common causes: Common causes include Faulty Brake Lamp Switch, Brake Lamp Switch harness is open or shorted, Brake Lamp 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.

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Code Popularity 5,141

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C1291 Description

The stop lamp switch signal informs the Electronic Brake Control Module (EBCM) when the brake pedal is pressed. The EBCM sets the OBDII code when the Brake Lamp Switch is not to factory specifications.

OBDII Code C1291 - Open Brake Lamp Switch Contacts During Deceleration - AutoCodes.com — C1291 Code - Open Brake Lamp Switch Contacts During Deceleration

What does this mean?

What are the Possible Causes of the DTC C1291?

Faulty Brake Lamp Switch
Brake Lamp Switch harness is open or shorted
Brake Lamp Switch circuit poor electrical connection

How to Fix the DTC C1291?

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 C1291 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 C1291 code?

Need more information on how to fix the C1291 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C1291 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C1291 Buick — Open Brake Lamp Switch Contacts During Deceleration
C1291 Cadillac — Open Brake Lamp Switch Contacts During Deceleration
C1291 Chevrolet — Open Brake Lamp Switch Contacts During Deceleration
C1291 GMC — Open Brake Lamp Switch Contacts During Deceleration

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 Code

1. What are the common symptoms of OBDII code C1291?

When OBDII code C1291 is triggered, you may experience issues such as the brake lights staying on constantly or not illuminating at all, the brake pedal feeling spongy, or the vehicle going into limp mode.

2. What causes the OBDII code C1291 to be set?

The code C1291 is set when the brake lamp switch contacts are detected as open during deceleration, indicating a fault in the brake lamp switch circuit or the switch itself.

3. How can I diagnose the cause of OBDII code C1291?

To diagnose the cause of code C1291, you can start by checking the brake lamp switch for proper adjustment and continuity, inspecting the wiring and connectors for any damage, and testing the brake lamp switch operation during deceleration.

4. Can a faulty brake lamp switch be repaired, or does it need to be replaced?

In most cases, a faulty brake lamp switch will need to be replaced rather than repaired. It is a relatively inexpensive part and replacing it is a straightforward process in most vehicles.

5. Are there any DIY repair tips for resolving OBDII code C1291?

If you have experience working on vehicles, you can try adjusting the brake lamp switch to see if that resolves the issue. However, if the switch is found to be faulty, it is recommended to replace it to prevent further problems.

6. Will driving with OBDII code C1291 cause any safety hazards?

Driving with code C1291 may not directly affect the drivability of the vehicle, but it can compromise safety by causing the brake lights to malfunction. It is important to address the issue promptly to ensure proper brake light operation.

7. Can OBDII code C1291 be a false alarm?

While it is possible for a code to be triggered erroneously, it is important not to ignore code C1291, as it indicates a potential issue with the brake lamp switch that can impact safety and should be investigated.

8. How long does it typically take to repair OBDII code C1291?

The repair time for code C1291 can vary depending on the exact cause of the issue and the vehicle's make and model. In general, diagnosing and replacing a faulty brake lamp switch can be completed within an hour or two.

9. Will resetting the OBDII system clear code C1291?

Resetting the OBDII system may temporarily clear code C1291, but if the underlying issue with the brake lamp switch is not addressed, the code is likely to reappear once the problem is detected again during deceleration.

10. Is it safe to continue driving if OBDII code C1291 is present?

While the vehicle may still be operable with code C1291 present, it is advisable to address the issue promptly to ensure proper brake light functionality and avoid potential safety hazards on the road.