Testing the KOHLER Engine Speed Sensor (Crankshaft Position Sensor)

Hello again, fellow Technicians!

If your engine runs and there's no code 0336, the engine speed sensor is not the likely cause. A ridiculous number of these have been replaced, returned, and pass testing.

The most logical cause of misdiagnosis is probably seeing code 0337, which sets for other reasons discussed in a Service Bulletin shared in this video.

Early EFI engine models using this sensor (2009-2015ish) have an adjustable air gap, like an ignition coil. The spec for this gap is pretty forgiving (0.008-0.027"), though I usually find them set awfully close, and rust on the flywheel teeth can grow and eventually contact the sensor like the one seen in this video. The rust did not damage this sensor, nor was it causing any problems (yet). I reset the gap to 0.020"

Starting around 2014/2015, this sensor became fixed and no longer has an adjustable air gap. The fixed gap also seems to be around 0.020"

In the rare scenario that you find yourself with a 0336 and erratic run quality, pull the blower housing and CAREFULLY inspect the flywheel teeth and sensor. Make sure it's secured. Make sure there's nothing stuck to it (they can become magnetized during normal use-not a problem unless you lost a small washer or something). There will be 1 large gap between the teeth; this is so the ECU can determine TDC. Any broken or damaged teeth will confuse the ECU about TDC location. The same is true of a damaged or loose sensor; the ECU will lose TDC reference, resulting in improper engine timing and poor run quality (usually rich and sounds like an intermittent misfire). Gen 1 of the KOHLER Diagnostic Software (sold from about 1996-2018) has a line of data called "Loss of Sync Counter". In simple terms, this references the number of times TDC has been lost. If it reaches 2 while running, it's likely to exhibit a run quality fault and a 0336.

Lastly, the speed sensor wires are sensitive to interference, which is why they are twisted in the harness. If you have a 0336, the sensor is secure, the teeth are in good condition, the software may indicate multiple Loss of Sync Counts...you may have an electrical interference in the circuit. This is super rare, like winning lottery ticket rare, but can happen. Inspect routing of the charging lead to the B+ terminal of the rectifier-regulator, as it may be the source of interference if routed too close to the speed sensor wires.