Master Cylinder Internal Leak
The C0964 code means the vehicle's onboard diagnostic system has detected: Master Cylinder Internal Leak. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $200 - $800 (parts and labor)
Basic scanners cannot read ABS codes. BlueDriver reads all systems including ABS, SRS, and transmission through your phone.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Basic scanners cannot read ABS codes. This one reads all four systems so you know exactly which sensor failed.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Common Symptoms
- Brake pedal goes to floor
- Spongy brake pedal feel
- Brake warning light on
- Reduced braking effectiveness
Probable Causes (Ranked by Likelihood)
- Failed master cylinder internal seals Very High
- Low brake fluid level High
- Contaminated or old brake fluid Moderate
- Faulty brake pressure sensor Low
Step-by-Step Diagnostic Procedure
-
Check brake fluid level and condition
-
Test master cylinder for internal bypass
-
Inspect brake booster check valve
-
Test brake fluid moisture content
Frequently Asked Questions
What does code C0964 mean?
C0964 indicates a fault with the master cylinder internal leak.
Can I drive with C0964?
Do not drive. The brake system has a critical fault. Have the vehicle towed.
How much does it cost to fix C0964?
Typical repair costs are $200 - $800 (parts and labor).
Sources
This page is built from documented references. Verify against your own service info before repair work.
Explore More
Was this helpful?
Share carcodefinder.com with a friend who needs to decode their check engine light.