A failed brake pressure sensor K that internally shorts or drifts and reports a voltage higher than the actual brake pressure; Damaged or chafed wiring in the sensor circuit, especially where the harness flexes near the pedal assembly or ABS module; A poor ground connection or corroded connector terminal at the sensor or ABS module, which can bias the signal voltage high; Water intrusion or contamination in the sensor connector causing increased resistance and a high signal reading; A faulty ABS control module with an internal fault in the sensor input circuit, though this is less common than sensor or wiring problems; An open circuit in the sensor ground return, which can cause the signal voltage to float high

DTC codes / C06xx · Brakes, steering and suspension / C0642

C0642Brake Pressure Sensor K Circuit High

Q: What does code C0642 mean?

Brake Pressure Sensor K Circuit High. C0642 means the antilock braking system (ABS) module has detected an abnormally high voltage on the circuit for brake pressure sensor K, which is one of the sensors that reports how hard the driver is pressing the brake pedal. The computer expects the sensor signal to stay within a calibrated voltage window, and a reading above that window for a set time triggers this code.

C0642 means the antilock braking system (ABS) module has detected an abnormally high voltage on the circuit for brake pressure sensor K, which is one of the sensors that reports how hard the driver is pressing the brake pedal. The computer expects the sensor signal to stay within a calibrated voltage window, and a reading above that window for a set time triggers this code.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

ABS warning light illuminated on the dashboard, often accompanied by the traction control and stability control lights
A stored code in the ABS module with no other drivability symptoms, so the driver may notice nothing besides the warning light
Reduced or disabled ABS and traction control operation, which may only become apparent during hard braking or slippery conditions
Brake pedal feel that seems normal or slightly different, depending on whether the sensor signal is skewed high
In some vehicles, a message on the driver information display warning that stability control or hill start assist is unavailable

Common causes, most likely first

A failed brake pressure sensor K that internally shorts or drifts and reports a voltage higher than the actual brake pressure
Damaged or chafed wiring in the sensor circuit, especially where the harness flexes near the pedal assembly or ABS module
A poor ground connection or corroded connector terminal at the sensor or ABS module, which can bias the signal voltage high
Water intrusion or contamination in the sensor connector causing increased resistance and a high signal reading
A faulty ABS control module with an internal fault in the sensor input circuit, though this is less common than sensor or wiring problems
An open circuit in the sensor ground return, which can cause the signal voltage to float high

How to diagnose and fix it

Scan all modules and record the freeze-frame data for C0642, then clear the code and verify whether it returns immediately or only under specific braking conditions
Visually inspect the brake pressure sensor K, its connector, and the wiring harness for damage, corrosion, or loose pins, repairing any obvious faults
Measure the sensor reference voltage and ground at the sensor connector with a digital multimeter, comparing readings with the manufacturer's specification
Back-probe the sensor signal wire at the ABS module and compare the voltage with the sensor output to isolate whether the fault is in the sensor or the wiring
Perform a resistance and continuity test on the sensor ground circuit and repair any excessive resistance or open circuit
If the wiring and grounds test good, substitute a known-good brake pressure sensor K and recheck the live data to confirm the signal now tracks pedal pressure correctly
After repairs, clear the codes and perform a road test that includes ABS activation and stability control operation to confirm the code does not reset

What a high brake pressure signal really means

A high voltage on a pressure sensor circuit often indicates a lost ground or an open signal return rather than a failed sensor, so technicians who replace the sensor first may be disappointed when the code returns.
Brake pressure sensor K is frequently one of several pressure sensors in the ABS module, and a high reading on one sensor can be caused by a shared reference voltage or ground circuit that affects multiple sensors.
Some vehicles use the brake pressure sensor signal for hill start assist, adaptive cruise control, and electronic parking brake functions, so a fault here can disable features that seem unrelated to the brakes.
A pinched or stretched harness near the brake pedal bracket is a common cause that is easily missed during a visual inspection because the damage is hidden behind the pedal assembly.
The ABS module may set C0642 intermittently if the sensor connector is only partially seated, so always perform a wiggle test on the harness while watching live sensor voltage.

Can I keep driving with C0642?

You can usually drive the vehicle with C0642 set because the base brakes remain functional, but ABS and stability control are disabled, so avoid hard braking and slippery road conditions until the fault is repaired. If the brake pedal feels abnormal or the red brake warning light is also on, stop driving and have the vehicle inspected immediately.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.