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C0642 — Brake Pressure Sensor K Circuit High

Generic OBD-II · all makesChassis

Diagnostic trouble code C0642 indicates that the brake pressure sensor 'K' circuit is reporting a voltage higher than the expected range. This typically points to a short to power, an open circuit, or a failed sensor in the brake hydraulic system.

Symptoms

What causes it — most likely first

1. Faulty brake pressure sensor K

The sensor itself is the most common failure point, often due to internal short or damage.

2. Short to voltage in sensor signal circuit

Wiring harness damage, chafing, or pinched wires can cause the signal wire to contact a power source.

3. Open circuit or high resistance in sensor ground or signal wire

Corroded connectors, broken wires, or poor terminal fit can create an open or high-resistance path.

4. Corrosion or poor connection at sensor connector

Moisture ingress or loose terminals can cause intermittent high voltage readings.

5. Failed ABS/ESC control module

Rare, but internal module faults can cause incorrect voltage readings on the sensor circuit.

How it's diagnosed

  1. Retrieve all stored codes and freeze frame data to confirm C0642 and check for related codes.
  2. Visually inspect the brake pressure sensor K connector and wiring for damage, corrosion, or loose pins.
  3. Test the sensor's reference voltage and ground at the connector (typically 5V ref and good ground).
  4. Measure the sensor signal voltage with a multimeter while the brake is not applied; compare to manufacturer specifications.
  5. If signal voltage is high (e.g., near battery voltage), check for a short to power in the signal wire.
  6. If all sensor and wiring tests pass, suspect a fault in the ABS/ESC control module; perform module self-test or swap if possible.

Code facts & related codes

SystemChassis
StandardizationSAE generic — identical on every make
Related codesC0640 — Brake Pressure Sensor J RangeperformanC0641 — Brake Pressure Sensor K CircuitopenC0643 — Brake Pressure Sensor K Circuit LowC0644 — Brake Pressure Sensor K RangeperformanC0645 — Brake Pressure Sensor L CircuitopenC0646 — Brake Pressure Sensor L Circuit High

Frequently asked

Can I drive with code C0642?

It is not recommended as it may disable stability control and ABS, increasing stopping distances in emergencies.

Is this code always a bad sensor?

While the sensor is the most common cause, wiring issues and connector problems are also frequent. The control module is rarely at fault.

Do I need to replace the PCM for this code?

No. C0642 is a brake system code; the PCM is not typically involved. The ABS/ESC module may be a cause only after sensor and wiring are ruled out.