P0390Camshaft Position Sensor B Circuit Bank 2
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- Check engine light on
- Loss of power (bank 2 exhaust cam timing in its base position)
- Longer cranking
- Rough idle
- Higher fuel consumption
- Likely causes
- LikelyConnector or wiring of the bank 2 exhaust sensor open or corroded (signal, 5 V, ground)
- 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
- RareEngine module, or 5 V reference shorted by another sensor
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.