P2C35: Crankcase Pressure Sensor B Circuit High

What it means

The ECM detects a circuit high fault on the crankcase pressure sensor b circuit. Reading cannot be used reliably for control.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Crankcase pressure sensor B sends a signal to the ECM representing pressure in the crankcase. This high-circuit code sets when the signal voltage stays above the expected range, which can result from a signal short to battery voltage or an open sensor circuit.

Common causes

Most likely first.

1. Signal wire shorted to B+
2. Open sensor
3. Connector pins corroded - high contact resistance

Symptoms

• Check-engine light
• Rough or uneven idle
• Lower fuel economy

How to diagnose it

1. Review freeze-frame data and live sensor B readings to confirm the signal is high when the fault occurs.
2. Inspect sensor B's connector and harness for loose or corroded pins, broken conductors, and wiring shorted to a power feed.
3. Using the wiring diagram, check the sensor B signal for a short to battery voltage and check for an open in the circuit.
4. Verify the sensor's reference and ground circuits, then test sensor B according to the manufacturer's procedure.
5. Repair the open, short, connection, or failed sensor found and confirm the signal returns to a plausible range.

Common fixes

• Repair a sensor B signal wire shorted to battery voltage.
• Repair an open wire or restore a secure connector contact in the sensor B circuit.
• Replace crankcase pressure sensor B if it is open or fails its specified test.
• Clear the code and verify sensor B output under normal running conditions.

Can I keep driving?

A short gentle drive is generally reasonable if the engine runs steadily, but avoid extended driving if rough idle or poor fuel economy appears. The ECM cannot rely on the high sensor B reading, so arrange diagnosis soon.