What it means
The module detects an implausible mismatch between vacuum sensor A and vacuum sensor B readings. The code alone does not identify which sensor or circuit is at fault.
How it works
The module compares vacuum sensor A and vacuum sensor B readings to check that they agree within a plausible range. This code sets when the two readings do not correlate; by itself it does not show which sensor, wiring path, or related system is responsible.
Common causes
Most likely first.
- Another ABS or stability control fault
- Low system voltage
- Module communication problem
- Calibration or configuration issue
Symptoms
- ABS or stability warning light
- Traction or stability control warning
- Reduced or disabled stability functions
How to diagnose it
- Scan the ABS or stability system for other codes and freeze-frame data, since a separate fault may have triggered the A/B mismatch.
- Compare live vacuum sensor A and sensor B readings under the same operating conditions to identify which value is implausible or whether both are affected.
- Check battery and system voltage, then inspect both sensors’ connectors and wiring for damage, corrosion, or poor connections.
- Check module communication and configuration or calibration status if both sensor signals appear reasonable but the correlation fault remains.
- Test each sensor and its circuit using the manufacturer’s procedure before deciding which component needs repair.
Common fixes
- Repair a low-voltage or poor battery connection affecting sensor readings.
- Repair a damaged connector or wiring fault in the affected sensor A or B circuit.
- Complete the specified calibration or configuration procedure if it is missing or incorrect.
- Resolve a related ABS or stability system fault that is disrupting the readings.
- Replace a sensor or module only after circuit and signal tests identify it as faulty.
Can I keep driving?
ABS, traction, or stability assistance may be reduced or disabled, although normal braking may remain. Drive cautiously and leave extra stopping distance, particularly on slippery roads, until the mismatch is diagnosed.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.