What P0394 means
Camshaft position sensor B is the exhaust camshaft sensor; bank 2 is the side without cylinder 1, so the code only occurs on V and boxer engines with one exhaust cam sensor per bank.
How the engine computer detects it
P0394 means the bank 2 exhaust cam signal now and then appears at a position where it is not expected relative to the crank reference – sporadic extra or missing edges. Ford checks this in its camshaft ignition system test from 200 rpm and decides within 5 s. FCA also uses the code and asks dealers to save the cam/crank synchronization event data before replacing parts, a hint that the sensor itself is often not the culprit. GM does not use P0394 and reports such faults under P0391. Typical causes are a loose contact, interference or a damaged tone wheel.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light on
- Sporadic jerking or stalling
- Occasionally longer cranking
Common causes
- Loose contact or corrosion at the sensor connector or harness Most likely
- Interference (ignition wiring, add-on devices, ground problems) Possible
- Tone wheel or phaser damaged, or sensor loose Possible
- Sensor faulty, temperature-dependent Possible
How to diagnose P0394
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: camshaft position sensor exhaust, camshaft tone wheel, sensor wiring, engine control module.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 3
- Ignition system or misfire
- 94
- Specific fault
Questions drivers ask
Can I drive with code P0394?
Drive gently and only as far as you need to. The engine computer may limit power to protect the engine, so avoid highways and heavy traffic until it's fixed. If the check engine light starts flashing, pull over.
Will my car pass an emissions inspection with P0394?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Can I fix P0394 myself?
Often yes, with an OBD-II scanner and basic tools. Difficulty: medium. Start with the cheapest checks before replacing expensive parts.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.