P0391

Symptoms

• Unstable engine operation
• Power reduction
• Increased fuel consumption
• Check Engine Light Illuminates
• Problems starting the engine

Causes

• Camshaft Position Sensor B Malfunction
• Open or shorted wiring harness
• Poor contact in the sensor connector
• Power or grounding problems
• Mechanical timing problems (chain, gears)
• Sensor contamination with metal shavings

How to Fix

1. Check sensor parameters with a scanner
2. Visually inspect the sensor and wiring harness
3. Check the contacts in the sensor connector
4. Measure the resistance and voltage of the sensor
5. Replace sensor if necessary
6. Check the condition of the timing chain and marks

Related codes

Error P0391 by Vehicle Brand