Code
C05C7
Generic
C — Chassis
Brake Pressure Sensor F Circuit High
Views:
UK: 12
EN: 24
RU: 13
AI status
Completed
Completed
100%
Causes
- Short to battery voltage in the sensor signal circuit
- Faulty/failed brake pressure sensor F (internal short or calibration loss)
- Open or poor ground for the sensor reference ground
- Corroded, bent or damaged connector pins / poor connector fit
- Damage to harness (chafing, pinched, water intrusion)
- Faulty ABS/brake control module or internal input circuit
Symptoms
- ABS, ESC or brake warning lamp illuminated
- Brake system warning message or limited braking functionality in some vehicles
- Stored DTC(s) and possibly limited ABS/traction control operation
- Brake feel may be normal if sensor issue is only electrical (mechanical failure not always present)
- Possible multiple related pump/module codes if the module detects inconsistent pressure inputs
What to check
- Read and record freeze-frame and live data with an OBD-II / dealer scan tool (ABS module data)
- Check for additional ABS/traction/brake-related DTCs
- Visual inspection of sensor F connector, wiring harness and nearby components for damage, corrosion or fluid exposure
- Wiggle test wiring while monitoring live sensor signal for intermittency
- Backprobe the sensor harness to measure reference voltage, ground continuity and signal voltage with ignition on
- Measure continuity and resistance between sensor ground and chassis battery negative
Signal parameters
- Typical sensor type: analog pressure sensor with a 0.5–4.5 V (approx) output—varies by manufacturer
- Expected idle (no brake pressure) voltage: often low (around 0.5–1.0 V) and increases with pressure
- Reference supply: typically a regulated 5 V reference from the control module
- Signal behavior: voltage should change smoothly with applied hydraulic pressure; abrupt saturation near battery voltage suggests short to Vb or sensor failure
- If vehicle uses CAN/frequency output, expect a defined data packet or frequency range—consult service manual for exact numbers
Diagnostic algorithm
- Connect a capable scan tool, read all stored codes and freeze-frame data, and note related ABS/brake codes.
- Visually inspect sensor F connector and wiring for corrosion, loose pins, melted insulation, or signs of fluid intrusion. Repair any obvious damage.
- With ignition ON (engine off), backprobe the sensor connector: verify 5 V reference (or manufacturer-specified reference), good ground (low ohm to chassis), and measure signal voltage. Compare to expected ranges from service data.
- Wiggle the wiring harness and connector while watching live data for intermittent jumps to high voltage. Repair wiring faults if present.
- If supply and ground are good but signal is high (near battery voltage), disconnect the sensor and measure open-circuit voltage at the module end to check for short to Vb in harness or module.
- Apply known brake pressure (pedal or calibrated pressure tool) while monitoring signal voltage to confirm sensor output changes smoothly. If sensor does not change or remains high, suspect sensor or internal short.
- If wiring is good and sensor output is still out of range after bench or subsystem tests, replace the brake pressure sensor F per service procedure.
- If replacement does not clear the issue, test or replace the ABS/brake control module only after confirming wiring and sensor integrity.
- Clear codes, road test and re-scan to confirm repair. Document results and re-check for intermittent faults.
- Note: consult vehicle-specific service manual for exact voltage ranges, pin assignments, and safety procedures before applying power or disconnecting hydraulic components.
Likely causes
- Short to 12V on the sensor signal wire at a connector or within harness
- Internal sensor failure where output saturates high
- Connector corrosion or bent pin pulling signal toward supply voltage
- Missing or poor ground reference causing the module to interpret the signal as high
- Intermittent wiring damage creating high readings under some conditions
Fault status
Status
Brake Pressure Sensor F — Circuit High. Signal above expected range (possible short to battery, sensor failure, or wiring/connector fault).
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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