General Information

Engine Control
P0391 Camshaft Position Sensor 'B' Circuit Range/Performance (Bank 2) - General Information

Component Location





General Description

The Camshaft Position Sensor (CMPS) is a sensor that detects the compression TDC of the NO. 1 cylinder. The CMPS consists of a hall type sensor and a target on the end of the intake camshaft. When the target triggers the sensor, the sensor voltage is 5 V. If not, the sensor voltage is 0 V. These CMPS signal is sent to the ECM and the ECM uses the CMPS signal for synchronizing the firing of sequential fuel injectors.

DTC Description

Checking output signals from CMP during engine running, if the expected number of cam tooth count is not observed, ECM sets P0391.

DTC Detecting Condition





Diagnostic Circuit Diagram





Signal Waveform & Data




Fig 1) Normal waveform of IN-CMPS & EX-CMPS at idle.