C0642

Code

Generic C — Chassis

Brake Pressure Sensor K Circuit High

Brand: Generic

Type: C — Chassis

Views: UK: 23 EN: 38 RU: 27

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Short to battery voltage on the brake pressure sensor signal wire
Open or damaged sensor wiring with intermittent contact
Corroded or poor connector at sensor or control module
Failed brake pressure sensor (internal fault)
Faulty ABS/brake control module or poor module ground
Water intrusion or contamination in sensor connector / harness

Symptoms

ABS warning lamp illuminated
Brake system or traction control warning lights illuminated
Reduced or disabled ABS/traction control functions
Possible diagnostic trouble codes stored for brake pressure sensor
No obvious change to basic pedal feel in many cases

What to check

Retrieve freeze-frame and live data from ABS/brake module
Verify other related DTCs present (cross-check for harness faults)
Visual inspection of sensor, connector and wiring for damage or corrosion
Backprobe sensor connector and measure signal and reference voltages
Check continuity and shorts to battery and ground on the signal and supply wires
Wiggle test wiring while monitoring live data for intermittent faults

Signal parameters

Typical brake pressure sensor reference: 5 V (verify with vehicle data)
Expected sensor output: ~0.5–4.5 V proportional to pressure (varies by design)
High-circuit fault: signal voltage above expected max (often approaching supply/battery voltage)
Low-circuit fault: signal voltage near 0 V
Sensor supply current typically low; short to power will raise signal voltage

Diagnostic algorithm

Safety: Park vehicle, apply parking brake, follow manufacturer safety procedures before working near brake system.
Read and record DTCs and freeze-frame data with a scan tool; note related codes and history.
Visually inspect sensor and harness for damage, corrosion, pins pushed out, or water intrusion at the sensor and at the module connector.
Backprobe sensor connector and with ignition ON (engine off unless specified), measure reference voltage, signal voltage, and ground using a digital multimeter. Compare to expected ranges.
If signal voltage is high, disconnect the sensor and re-measure signal at the harness side. If voltage returns to normal with sensor disconnected, suspect the sensor. If still high, suspect wiring short to power or module.
Check continuity of signal and reference wires between the sensor and the ABS/brake control module; check for short to battery (measure resistance to B+ with ignition OFF) and short to ground.
Perform wiggle test on wiring while monitoring live data for intermittent changes. Repair any damaged wiring or connectors found.
If wiring and connectors are good and sensor is new/known good but fault persists, consider swapping or bench-testing sensor per service manual, then evaluate control module input. Replace module only after confirming harness and sensor integrity.
After repairs, clear codes, perform functional/road test and re-scan to confirm the fault does not return.

Likely causes

Short to power on sensor signal or supply wire
Faulty or internally shorted brake pressure sensor
Corroded/loose connector at sensor or module
Damaged wiring harness (pinched/chewed) between sensor and module
Module input stage fault (less common)

Fault status

⚠️ Status

C0642 — Brake Pressure Sensor K Circuit High: The brake pressure sensor signal line is above the expected voltage range. ABS/brake warning lights may be set and ABS/traction functions may be affected. Check sensor, wiring and module inputs.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours