P0391 OBD-II: Camshaft Position Sensor "B" Circuit Range/Performance
P0391 Severity
Should you fix P0391 yourself?
Identifying an OBD code is just the start of a complete diagnostic routine. Most trouble codes are caused by a sensor reporting a value that is out of range. Just replacing a sensor may not fix underlying issues. Be sure to understand the code, the part or system in your car that the code refers to, and the risks of delaying professional repair.
Proper diagnosis will save you time and money on unnecessary repairs.
Urgent codes indicate immediate action is necessary. These are urgent and significant malfunctions that can cause severe damage to the vehicle or harm the driver and passengers.
What causes OBD-II fault code P0391?
The Camshaft Position Sensor measures the exact rotational position of the camshaft. This provides a critical data signal used by the engine control module (PCM) to control the fuel injectors and ignition coils. When the PCM detects an irregular signal or no signal, it will set code P0391.
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