Camshaft Position Sensor Circuit Range/Performance (Bank 2)
The P0391 code indicates that the Engine Control Module (ECM) has detected a malfunction in the camshaft position sensor circuit for Bank 2. This sensor monitors the position of the camshaft relative to the crankshaft to ensure proper timing for fuel injection and ignition. The 'Range/Performance' aspect means the signal from the sensor is out of expected parameters, often due to a faulty sensor, wiring issues, or timing chain/belt problems. Bank 2 refers to the side of the engine opposite cylinder #1.
1. Most Common Causes
- Faulty camshaft position sensor (Bank 2)
- Wiring or connector issues (shorts, opens, corrosion)
- Timing chain/belt stretched or jumped
- Engine mechanical problems (low oil pressure, worn components)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Hard starting or stalling
- Reduced engine power and fuel economy
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the camshaft position sensor and wiring for damage or corrosion.
Step 3: Test sensor resistance and voltage with a multimeter per manufacturer specs.
Step 4: Check timing chain/belt alignment and tension.
Step 5: Replace sensor if faulty, repair wiring, or address timing issues.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause engine misfires, stalling, and potential damage to the catalytic converter or engine.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a sensor replacement, but can be higher if timing chain repairs are needed.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.