P0390 code meaning
Camshaft Position Sensor B Circuit Bank 2
Powertrain system Generic code P03xx codes Check engine light
What P0390 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. P0390 means no or too few exhaust cam pulses arrive from bank 2 while the crankshaft turns. GM's 3.0 twin-turbo V6 (LGW) sets it after 5.5 s without a cam pulse, 4 s of cranking or fewer than 4 pulses in 3 s, after two trips; for GM it collects all circuit faults. GM's 3.6-litre V6 in the Saab 9-4X also counts 800 of 1,000 engine cycles without a pulse. Ford checks the crank-to-cam ratio from 200 rpm within 5 s, and the 2004 Northstar counts missing signal changes up to 16. The bank 2 exhaust phaser then locks in its base position; the engine keeps running on the crank and intake cam sensors. FCA advises saving the synchronisation data before replacing the sensor.
P0390 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P0390
- Check engine light on
- Loss of power (bank 2 exhaust cam timing in its base position)
- Longer cranking
- Rough idle
- Higher fuel consumption
Common causes of P0390
- Most likelyConnector or wiring of the bank 2 exhaust sensor open or corroded (signal, 5 V, ground)
- Most likelyCamshaft position sensor faulty
- PossibleOil contamination or leak at the sensor, sensor loose
- PossibleTone wheel on the phaser damaged or wrongly fitted after timing chain work
- Less likelyEngine module, or 5 V reference shorted by another sensor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Camshaft position sensor exhaustCamshaft tone wheelSensor wiringEngine control moduleCam phaser exhaust bank2
What each part of P0390 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3 | Area: ignition system or misfire. |
| 90 | The exact fault in that area. |
What to do next
- Note P0390 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0390
What does P0390 mean?
P0390 means "Camshaft Position Sensor B Circuit Bank 2". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0390?
Drive gently and only to a workshop. With P0390 the car can go into limp mode (reduced power) to protect itself.
Will P0390 fail an emissions test?
Yes, it can. P0390 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0390 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0390 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.