DTC P0340: Camshaft Position Sensor "A" Circuit (Bank 1 or Single Sensor): Description

The Camshaft Position (CMP) sensor consists of a magnet and an iron core which is wrapped with copper wire, and is installed onto the cylinder head. When the camshaft rotates, each of 3 teeth on the camshaft passes the CMP sensor. This activates the internal magnet in the sensor, generating a voltage in the copper wire. The camshaft rotation is synchronized with the crankshaft rotation. When the crankshaft turns twice, the voltage is generated 3 times in the CMP sensor. The generated voltage in the sensor acts as a signal, allowing the ECM (included in the hybrid vehicle control ECU) to detect the camshaft position. This signal is then used to control ignition timing, fuel injection duration, and the VVT system.

HINT: 

DTC P0340 indicates a malfunction relating to the CMP sensor (+) circuit (the wire harness between the ECM and CMP sensor, and the CMP sensor itself).

Reference: Inspection using an oscilloscope

Fig 1: Identifying Oscilloscope Waveform Graph

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT: 

• The correct waveform is as shown in the illustration.
• G2+ stands for the CMP sensor signal, and NE+ stands for the Crankshaft Position (CKP) sensor signal.
• A failure of the ground for the shielding of the wiring may result in noisy waveforms.