P2C33: Crankcase Pressure Sensor B Circuit Range/Performance
What to do
The car will usually drive normally, and this is still worth having looked at.
This sensor watches the pressure inside the engine, which the ventilation system is supposed to keep slightly below atmospheric. When that goes wrong, the pressure pushes oil past the engine's seals — which shows up later as oil leaks and oil consumption rather than as anything you notice now.
Ask them to check the crankcase ventilation hoses first. A split or disconnected hose, or a blocked oil separator, is the usual cause and far cheaper than the sensor.
Two things worth mentioning if they apply: whether the engine has started using oil, and whether there is any oil misting around seals or the dipstick tube. Both point at the same system and help the diagnosis.
What this code means
Crankcase pressure sensor B is reporting an implausible value.
A crankcase pressure sensor watches the pressure inside the engine's own bottom end, and it is there for two quite different reasons.
Every engine leaks a little combustion gas past its piston rings into the crankcase — blow-by. The ventilation system draws that away and returns it to the intake, and it must maintain a slight depression: too much pressure pushes oil past seals, too much vacuum collapses them.
The second reason is diagnostic, and it is why this sensor exists on modern engines at all. Crankcase pressure is a direct measure of engine health: rising blow-by means worn rings or bores, and emissions regulation increasingly requires the engine to notice its own ventilation system being disconnected or blocked.
So an implausible reading here is worth taking seriously even though the car drives normally, because the system it belongs to protects the seals whose failure produces oil leaks and oil consumption.
The commonest causes are the ventilation plumbing rather than the sensor — a disconnected or split hose, or a blocked oil separator — which is exactly what the neighbouring codes at P2C90 and P2C91 name directly.
Why this page exists when its neighbours do not. Nothing in the public web documents this block — four independent searches established that on 2026-08-10. This code is written because a manufacturer named it, with its definition, in a technical service bulletin filed with the US road safety regulator, and that OEM wording agrees with the standard's own enumeration. Its neighbours have no such document, so they remain undocumented rather than guessed.
Likely causes
Start here
- Leaking or perished vacuum hose · moderate
- Corroded or loose connector · easy
Less common
- Damaged wiring harness · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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