Code
C05A0
Generic
C — Chassis
Brake Pressure Sensor E Circuit High
Views:
UK: 10
EN: 31
RU: 19
AI status
Completed
Completed
100%
Causes
- Open or short in sensor wiring (short to battery voltage)
- Failed brake pressure sensor (internal short or internal reference failure)
- Poor or corroded connector pins at sensor or ECU
- Loss of sensor ground or poor reference ground
- Faulty ABS/brake control module (rare)
- Aftermarket device or recent repair damage to harness
Symptoms
- ABS/ESC/brake warning lamp illuminated
- Reduced or altered ABS/ESC function (warning and degraded braking control)
- Brake pedal feel may be normal or altered depending on system
- Possible fault memory with stored freeze-frame/live data
- No-start restrictions or limp/limited stability control in some vehicles
What to check
- Retrieve freeze-frame and live-data with a scan tool; note sensor voltage and related channels
- Visually inspect sensor, connector, and wiring for damage, corrosion, or pin push-out
- Backprobe sensor signal, reference, and ground with ignition ON and observe voltages
- Perform wiggle test on harness while monitoring signal for intermittent changes
- Check connector mating at the ABS/brake control module and inspect for corrosion
- Scan for additional ABS/vehicle stability codes that may point to common faults
Signal parameters
- Sensor is an analog pressure sensor; expected output typically in the 0.5–4.5 V range proportional to pressure (vehicle-specific)
- Reference supply usually ~5 V from the ABS/brake ECU
- Circuit-high condition typically flagged when sensor signal > ~4.5–4.8 V or near battery voltage
- Short-to-battery will show sensor voltage near vehicle battery voltage (10–14 V with ignition on)
- Open-circuit can also show anomalous high readings on some control modules (depends on module input pull-up)
Diagnostic algorithm
- Safety first: park on level ground, chock wheels, remove ignition key or disable vehicle according to safety procedures.
- Read and record all ABS/brake codes and freeze-frame data with a diagnostic scanner. Note sensor voltage and related channels.
- Visually inspect the sensor connector and harness for damage, corrosion, pin misalignment, or recent repair work.
- With ignition ON (engine off), backprobe the sensor connector: measure signal voltage, reference (5 V) and ground. Compare to expected ranges.
- If signal is high at the sensor: disconnect the sensor and measure voltage on the harness signal wire at the disconnected connector. If voltage remains high, suspect wiring short to battery or ECU pull-up.
- Check continuity and for short to battery: with battery disconnected, measure resistance between the signal wire and battery positive to check for short. Also check continuity from signal to ECU pin.
- Inspect and test ground circuits: verify good ground continuity from sensor ground to chassis/battery negative.
- If wiring and connectors OK and signal only becomes normal when sensor disconnected, replace the brake pressure sensor and retest.
- If sensor replacement does not clear the code and wiring/grounds are good, test or replace the ABS/brake control module or consult manufacturer procedures (module bench test or reflash may be required).
- After repairs, erase codes and perform a road test or required relearn procedures while monitoring live data to confirm the fault is resolved.
Likely causes
- Corroded/loose connector at the brake pressure sensor
- Short to battery voltage on the sensor signal or reference wire
- Failed sensor producing abnormally high output voltage
- Poor ground at sensor or shared ground point
- Intermittent wiring break contacting a power source
Fault status
Status
Brake Pressure Sensor E circuit voltage above expected range (Circuit High) — diagnostic required.
Repair difficulty: Medium
Diagnostic time: 1.0 - 2.5 hours
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