P0390
Camshaft Position Sensor "B" Circuit (Bank 2)
The engine computer is not getting a correct signal from the bank 2 sensor B camshaft position circuit. On many engines sensor B refers to the exhaust cam on bank 2. The problem is usually the sensor, connector, wiring, or a timing issue affecting the signal.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20-$150
- SHOP
- $120-$500
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Faulty bank 2 camshaft position sensor B
- Damaged, loose, or corroded connector at the sensor
- Broken, shorted, or rubbed-through wiring in the sensor circuit
Typical repair cost
DIY usually runs $20-$150. Typical shop repair lands around $120-$500, depending on the root cause.
01 / Definition
P0390 means the PCM has detected a malfunction in the bank 2 camshaft position sensor B circuit. The control module is not receiving the expected signal, or the signal is missing, intermittent, or electrically faulty. On many vehicles this affects ignition timing, fuel injection timing, and variable valve timing control.
02 / Drive status
With caution. Short trips may be possible, but the engine can run rough, stall, or become hard to start. If the engine misfires badly or dies, stop driving and repair it.
03 / Symptoms
- Check engine light
- Hard starting
- Extended cranking
- Rough idle
- Misfires
- Poor acceleration
- Stalling
- Reduced fuel economy
04 / Causes
| 1 | Faulty bank 2 camshaft position sensor B | high |
|---|---|---|
| 2 | Damaged, loose, or corroded connector at the sensor | high |
| 3 | Broken, shorted, or rubbed-through wiring in the sensor circuit | high |
| 4 | Oil contamination or moisture in the connector or sensor | medium |
| 5 | Timing chain, cam phaser, or mechanical timing problem affecting correlation | medium |
| 6 | PCM fault | low |
05 / Diagnostic sequence
- 01Confirm the code and check for related crankshaft, camshaft, timing, or misfire codes.
- 02Inspect the bank 2 sensor B camshaft position sensor connector for looseness, corrosion, oil, or damaged terminals.
- 03Inspect the harness for broken wires, rubbing, melted insulation, or contact with hot engine parts.
- 04Check sensor power, ground, and signal with a scan tool or multimeter according to the wiring diagram.
- 05Compare the bank 2 sensor B signal to known-good cam or crank data if the scan tool supports it.
- 06Inspect engine oil condition and check for timing chain or cam phaser noise if the circuit tests good.
- 07Replace the sensor only after confirming the wiring and power supply are correct.
- 08Clear the code and confirm the repair during a road test.
06 / Repairs
| 1 | Repair damaged wiring, poor grounds, or loose connector terminals in the sensor circuit | $20-$150 |
|---|---|---|
| 2 | Replace the bank 2 camshaft position sensor B | $40-$250 |
| 3 | Repair oil leaks or contamination affecting the sensor or connector | $50-$300 |
| 4 | Repair timing chain, cam phaser, or mechanical timing faults if confirmed | $300-$1,500+ |
| 5 | Diagnose PCM faults only after all circuit and timing checks pass | $100-$800 |
07 / Related codes
08 / FAQ
What does P0390 mean?
It means the PCM found a fault in the bank 2 camshaft position sensor B circuit.
Is P0390 always a bad camshaft sensor?
No. Wiring, connectors, oil contamination, and timing problems can also cause it.
What is bank 2 sensor B?
Bank 2 is the engine side without cylinder 1. Sensor B is often the exhaust cam sensor, but naming varies by manufacturer.
Can P0390 cause a no-start?
On some vehicles it can cause long cranking or a no-start, especially if the PCM cannot trust cam timing data.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.