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Engine-Codes – Generic – C1391

C1391 Code - Abnormal Leak Of Accumulator Pressure

Quick Answer

The diagnostic code C1391 indicates an abnormal leak of accumulator pressure in the vehicle's braking system. Common causes include Damaged accumulator seals, Corrosion or rust on accumulator components, Faulty pressure sensor. 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
C1391 indicates Abnormal Leak Of Accumulator Pressure.
Common causes
Common causes include Damaged accumulator seals, Corrosion or rust on accumulator components, Faulty pressure sensor.
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.
What is this?
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code C1391 Description

The diagnostic code C1391 indicates an abnormal leak of accumulator pressure in the vehicle's braking system. The accumulator is a component that stores hydraulic pressure to assist with brake actuation. When there is a leak in the accumulator, it can lead to a decrease in brake performance, potentially causing issues with braking efficiency and response. This can compromise the safety of the vehicle, as the brakes may not function properly in emergency situations. If not addressed, the abnormal leak of accumulator pressure can lead to further damage to the braking system and other related components.

OBDII Code C1391 - Abnormal Leak Of Accumulator Pressure
C1391 Code - Abnormal Leak Of Accumulator Pressure

Common Causes of C1391

  1. Damaged accumulator seals
  2. Corrosion or rust on accumulator components
  3. Faulty pressure sensor
  4. Accumulator bladder failure
  5. Accumulator housing leaks

Symptoms of C1391

  1. Soft or spongy brake pedal
  2. Increased stopping distance
  3. Brake warning light illuminated on the dashboard
  4. Loss of brake pressure during braking
  5. Unusual noises coming from the braking system

How to Fix C1391

  1. Inspect the accumulator and brake system for leaks and damage.
  2. Replace damaged accumulator seals or bladder.
  3. Repair or replace any corroded or rusted accumulator components.
  4. Test the brake system to ensure proper pressure and functionality.
  5. Reset the fault code and perform a final check to confirm the issue has been resolved.

Cost to Fix C1391

The cost of repairing an abnormal leak of accumulator pressure can vary depending on the extent of the damage and the specific components that need to be replaced. On average, the repair for this issue can range from $200 to $500, including parts and labor. It is important to note that these costs are estimates and actual prices may differ based on the location, vehicle make and model, and the specific repair shop. It is recommended to obtain multiple quotes from reputable auto repair shops to ensure a fair price for the repair.

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Code C1391 Information for Specific Makes

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 C1391 Code

1. What are the common symptoms of OBDII code C1391 (Abnormal Leak of Accumulator Pressure)?

Symptoms may include a soft or spongy brake pedal feel, the ABS warning light illuminating on the dashboard, and potential loss of braking performance.

2. What are the possible causes of OBDII code C1391?

The code C1391 typically indicates an abnormal leak of accumulator pressure in the ABS system, which can be caused by a faulty accumulator, a leaking hydraulic unit, or a malfunctioning ABS pump.

3. How serious is OBDII code C1391?

Code C1391 should be addressed promptly, as it can lead to compromised braking performance and potential safety hazards. It is advisable to have the issue diagnosed and repaired as soon as possible.

4. Can driving with OBDII code C1391 pose any risks?

Continuing to drive with code C1391 may result in reduced braking effectiveness, especially during sudden stops or emergency situations. It is recommended to address the issue promptly to ensure safe driving conditions.

5. How can I diagnose OBDII code C1391?

Diagnosing code C1391 typically involves using a professional OBDII scanner to read the fault codes stored in the ABS system. A comprehensive inspection of the ABS components may be necessary to pinpoint the exact cause of the issue.

6. What are some DIY repair tips for OBDII code C1391?

DIY repair for code C1391 may involve checking for visible leaks in the ABS system, inspecting the accumulator and hydraulic unit for damage, and ensuring proper fluid levels. However, it is recommended to consult a professional mechanic for a thorough diagnosis and repair.

7. Can I reset OBDII code C1391 on my own?

Resetting the OBDII code C1391 may temporarily clear the fault code, but the underlying issue causing the abnormal leak of accumulator pressure will persist. It is best to address the root cause of the problem to prevent the code from reoccurring.

8. How much does it cost to repair OBDII code C1391?

The cost of repairing code C1391 can vary depending on the specific cause of the issue, the extent of the damage, and labor costs. It is advisable to obtain estimates from reputable mechanics or service centers for an accurate assessment.

9. Is it safe to drive my vehicle to the repair shop with OBDII code C1391?

If you experience symptoms like a soft brake pedal or decreased braking performance, it is not recommended to drive the vehicle to the repair shop. Arrange for towing or professional assistance to avoid potential safety risks on the road.

10. Can OBDII code C1391 be a recurring issue after repair?

If the root cause of code C1391 is not properly addressed during the repair, it may resurface as a recurring issue. To prevent this, ensure that the ABS system is thoroughly inspected, any faulty components are replaced, and proper maintenance is conducted.

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