ABS System Pressure Circuit Malfunction
What does C0133 mean?
The C0133 code means the vehicle's onboard diagnostic system has detected: ABS System Pressure Circuit Malfunction. This is a critical severity code.
Common Symptoms
- ABS light on
- Firm or pulsating brake pedal
- ABS system inoperative
- Traction control disabled
- Unusual noises from ABS module during braking
Probable Causes (Ranked by Likelihood)
- Failed ABS pressure accumulator Very High
- ABS hydraulic pump not building pressure High
- Pressure sensor within ABS module failure Moderate
- Internal hydraulic valve blockage Low
Step-by-Step Diagnostic Procedure
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Scan ABS module for pressure-related DTCs
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Check ABS pump operation during system self-test
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Monitor system pressure data with scan tool
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Inspect ABS hydraulic unit for external leaks
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Test ABS pump motor function
Frequently Asked Questions
What is the ABS pressure accumulator?
The accumulator stores pressurized brake fluid for rapid ABS activation. When it fails, the ABS system cannot respond quickly enough during an anti-lock braking event.
Can old brake fluid cause pressure issues?
Yes. Brake fluid absorbs moisture over time, which lowers its boiling point and can cause internal corrosion in the ABS hydraulic components, leading to pressure circuit problems.
How often should brake fluid be changed?
Most manufacturers recommend brake fluid replacement every 2-3 years or 30,000-45,000 miles. Regular flushing helps maintain ABS component health.