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DTC codes / P2Cxx · Hybrid propulsion / P2C35

P2C35Crankcase Pressure Sensor B Circuit High

P2C35 means the powertrain control module (PCM) has detected an abnormally high voltage signal on the circuit for crankcase pressure sensor B, which is used to monitor pressure inside the engine crankcase. The PCM expects the sensor's output to stay within a calibrated voltage range, and a reading above that range indicates an open circuit, a short to voltage, or a sensor that is not returning a valid signal.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Rough idle or unstable engine operation if crankcase pressure is genuinely abnormal
  • Oil leaks or oil mist around seals and gaskets due to excessive crankcase pressure
  • A whistling or hissing noise from the engine bay caused by a blocked or failed crankcase ventilation system
  • Reduced engine performance or poor fuel economy in some cases
  • Possible transmission shift harshness on vehicles that use crankcase pressure data for load calculations

Common causes, most likely first

  1. Open circuit or high resistance in the sensor B signal wire, such as a broken wire or corroded connector
  2. Short to voltage on the signal circuit, often from chafed wiring near the engine block
  3. Failed crankcase pressure sensor B that is internally open or has drifted out of calibration
  4. Poor electrical connection at the sensor or PCM connector, including loose pins or water intrusion
  5. Blocked or restricted crankcase ventilation system causing pressure to exceed the sensor's normal range
  6. PCM software issue or internal fault in the pressure sensor input circuit, though this is less common

How to diagnose and fix it

  1. Connect a scan tool and record the freeze-frame data for P2C35, then clear the code and verify whether it returns immediately or only under specific conditions.
  2. Visually inspect the crankcase pressure sensor B, its connector, and the wiring harness for damage, corrosion, or loose pins, repairing as needed.
  3. Use a digital multimeter to check the sensor's reference voltage and ground at the connector, confirming the PCM is supplying the correct 5-volt reference and a good ground.
  4. Back-probe the signal wire and compare the sensor's output voltage against the manufacturer's specification while the engine is running at idle and at higher RPM.
  5. Check the crankcase ventilation system for blockages, collapsed hoses, or a stuck PCV valve that could cause pressure to rise beyond the sensor's normal range.
  6. If the signal circuit and ventilation system are good, substitute a known-good sensor B and recheck the live data to confirm the fault follows the sensor.
  7. After repairs, clear the codes and perform a road test with the scan tool monitoring crankcase pressure to confirm the code does not reset.

What the voltage reading really tells you

  • A high voltage on a pressure sensor circuit almost always means the signal wire is open or shorted to voltage, not that the sensor itself has failed, so resistance and voltage-drop tests on the harness come before parts replacement.
  • Some vehicles use crankcase pressure sensor B as part of the evaporative emissions or turbocharger control strategy, so a P2C35 can be accompanied by drivability complaints that seem unrelated to the crankcase.
  • A blocked PCV system can push crankcase pressure high enough to set this code even when the sensor and wiring are perfectly healthy, so always verify ventilation flow before condemning the sensor.
  • Intermittent P2C35 codes often trace to a chafed wire near a hot exhaust component or a connector that fills with oil from a leaking sensor seal, which a simple wiggle test may not reveal.
  • Do not assume the PCM is faulty because the code persists after sensor replacement; check for a short to voltage on the signal circuit with the PCM disconnected before considering module replacement.

Can I keep driving with P2C35?

You can usually drive the vehicle short distances to a repair shop, but avoid sustained high-speed driving or heavy load because a genuine crankcase pressure fault can force oil past seals and cause leaks. If you notice oil smoke, a loud whistling noise, or rough running, stop driving and have the vehicle inspected promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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