How to Test the Camshaft Position Sensor for Faults?
2 Answers
Camshaft position sensor testing method: The measurement is based on a Hall integrated circuit, where the output signal shows a low state via the tooth surface and a high state via the gap. The camshaft sensor operates on the same principle as the crankshaft sensor, but the camshaft sensor's tooth disk has fundamental differences. Using a special blocking template allows for emergency operation after the crankshaft sensor fails, but the resolution of the camshaft sensor signal is too inaccurate to replace the crankshaft sensor under normal operation. The camshaft position sensor is one of the critical sensors in the engine's electronic control system, providing the vehicle's ECU with signals to confirm piston position, thereby determining the engine's ignition timing and sequential fuel injection.
I conducted a DIY inspection of the camshaft position sensor. First, I started the engine to check if the malfunction indicator light was on, then used an OBD scanner to read the fault codes. If codes like P0340 appear, they require special attention. Next, I turned off the engine and disconnected the negative battery terminal, located the sensor connector on the engine and unplugged it, checking for rust or oil contamination on the pins. Using a multimeter set to the resistance mode, I measured the sensor's resistance to ensure it was within the 500-2000 ohm range—values outside this range typically indicate failure. Finally, I reconnected the sensor, started the engine, and measured the signal wire voltage, which should pulse between 0.1V and 5V under normal conditions. A fixed voltage suggests a signal fault. Throughout the process, I wore insulated gloves, paying special attention to potential cracks in the aging sensor wiring harness.
