AutoCodes – Generic – C1391

C1391 Code - Abnormal Leak Of Accumulator Pressure

Quick Answer

The Diagnostic Trouble Code (DTC) is stored if a brake fluid, internal or other leak is detected due to improper sealing in the actuator. Common causes include Fluid Leakage, Faulty Brake Actuator Assembly, Brake Actuator Assembly harness is open or shorted. 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 Fluid Leakage, Faulty Brake Actuator Assembly, Brake Actuator Assembly harness is open or shorted.
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 34,995

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 27, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C1391 Description

The Diagnostic Trouble Code (DTC) is stored if a brake fluid, internal or other leak is detected due to improper sealing in the actuator. Internal leakage is suspected if the pump motor operates frequently without breaking.

OBDII Code C1391 - Abnormal Leak Of Accumulator Pressure - AutoCodes.com — C1391 Code - Abnormal Leak Of Accumulator Pressure

What does this mean?

What are the Possible Causes of the DTC C1391?

Fluid Leakage
Faulty Brake Actuator Assembly
Brake Actuator Assembly harness is open or shorted
Brake Actuator Assembly circuit poor electrical connection

How to Fix the DTC C1391?

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 C1391 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 C1391 code?

Need more information on how to fix the C1391 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C1391 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C1391 Lexus — Abnormal Leak Of Accumulator Pressure
C1391 Toyota — Abnormal Leak Of Accumulator Pressure

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.