P0340 Camshaft Position Sensor Circuit Malfunction
Intake camshaft sensor circuit
Exhaust camshaft sensor circuit
• After setting this DTC, the motor can rotate for a long period of time during start-up
• The exhaust camshaft position sensor is used to synchronize the injector and the ignition system. The engine may be throttled if the camshaft position sensor signal is interrupted and no DTC is generated. Inspect the inlet and outlet camshaft position sensor circuits for poor connections.
Circuit / system description code p0340
Each camshaft position sensor has 3 circuits consisting of a 5 V reference circuit supplied by the engine control module (ECM), a reference ground circuit, and an output signal circuit. The camshaft position sensor is an integrated sensing device with an internally magnetically charged digital output signal. The sensor detects changes in the magnetic flux between the teeth and grooves on the 4-tooth reluctor wheel mounted on the camshaft. The changes in the magnetic field caused by the passage of individual teeth of the reluctor wheel before the camshaft position sensor are used to generate a digital output pulse through the electronic sensor system. The sensor generates a two-state digital pulse of variable-frequency DC voltage with 4 output pulses with variable width for each camshaft rotation representing the camshaft reluctor camshaft image. The frequency of the camshaft position sensor output depends on the camshaft speed. The ECM decodes the gear pattern to identify the camshaft position. This information is then used to determine the optimal ignition characteristics and fuel injection in the engine. The ECM uses the exhaust camshaft position sensor to determine the synchronization of the injector and the ignition system. The intake camshaft and exhaust camshaft position sensors are also used to determine the relationship between the camshafts and the crankshaft. The ECM also uses the camshaft sensor output to determine the position of the shaft relative to the crankshaft to adjust the camshaft timing and operation in emergency program mode.