Crankshaft sensor
Could you advise me on crank angle sensors? Can I test the operation of the crank sensor with the engine running? I do not have an oscilloscope, but I do have VAG-COM.
My problem started with the EPC light on my Golf MKIV 2.0 8v. It would flicker occasionally, then the car began failing to start when it was hot after a long run; once the engine cooled, it would start fine.
I read off the fault code ‘16706 – Engine Speed Sensor (G28): No Signal P0322 – 35-10 – Intermittent’, so I removed the sensor and found it was wet with oil. I cleaned and refitted it, but this made no difference. The next day, I replaced the sensor with a Febi unit and I noted that the original sensor was wet with oil again when I removed it. The car has since started OK, but I still get the same error code, the car hesitates at higher revs and the EPC light flickers.
Is this something to do with oil contaminating the sensor? Or is it due to not fitting an original part? I have read on forums that some cars do not like nonoriginal crank sensors. Ivan Stockton The crank sensor operation is very unlikely to be affected by the oil on the outer surface. Basically very simple in operation, the sensor consists of a soft iron core, a magnet and a coil; the magnet field changes as a tooth on the crankshaft approaches the sensor and decreases as it moves away.
The symptom you had of the engine failing to start when hot is very common with a failed sensor. The sensor heats up normally, opening a break in the fine wire coil, then as the coil cools the circuit is remade, allowing the engine to start again. The easiest way to check the operation of the sensor is by using an oscilloscope to check the wave pattern. Using the VAG-COM you should be able to do this with the engine running by selecting ‘View live data by graph’.
The code ‘P0322' refers to ‘engine speed input circuit no signal’. Although this may well indicate that the crank sensor is faulty, it could also be triggered by a poor circuit in the loom between the sensor and the ECU. For this reason, I would also check the connections and the continuity of the loom between the terminals.
Providing the replacement sensor is up to specification it should work without problems.