Crank position sensor

[Chris Green90]

Due to some recent starting issues I replaced the starter motor on Dirty Gal today. Fired up first turn of the key but was knocking quite badly. never done that before.

Had a look around the starter because it is a PITA to remove and me being a little hamfisted at times figured I may have dislodged something. As it turned out I had broken one of the wire to a plug behind the starter and just above the line of the sump. This is the crank position sensor. so I dabbed the wire back on and the engine ran smoother. Excellent I thought. Turned the engine off and proceeded to cobble together a fix (difficult as the cable had broken right at the connector point.

Managed to bodge it for the time being and went to start the engine again. Nothing. cranks and cranks and cranks but no fire. checked the fault codes came back as 13. which is crank position sensor not giving a negative voltage within 2 secs of starter signal. or ECU.

So a couple of questions. I attempted to test the sensor pretty sure I was doing it right. hook up the multimeter both pins of the plug and crank the engine look for a voltage rising and falling. that seems to be there. Is this the right way to go about testing for a fault there???

Secondly is it likely that had the broken cable come into contact with the block or the positive starter input that it had sent the ECU to computer heaven???

or is there anything else I should be looking for??? Is there for example a proceedure for using fault codes. eg. realise there is a problem->diagnose the fault codes->fix problem->clear codes-> Just wondered if the ecu might not have reset due to the fault and was somehow protecting itself???

Any help would be great guys. Thanks

 

[Chris]

Chris it's basic, but often a cure for ECU hiccups. Disconnect the batteries and leave it a while.

 

[Jon Wildsmith]

I don't think a stored crank sensor fault would stop the engine firing if the crank sensor is now good but the ECU might still report the fault until it is cleared so you know what the light is on for? Like Chris said battery disconnect should clear it if there's not a simpler documented way. Then try again and if it comes right back then have another look at your fix. The ECU itself must be ok to be giving you a fault code. Hard to say if shorting the wire would kill the sensor circuitry in the ECU but they are usually fairly robust being designed for such a hostile environment.

 

[Beau]

Hopefully disconnecting the battery and leaving it overnight will help but if not I have a feeling connecting the wire back whilst the engine was running was bad idea and could possibly have damaged something, maybe the ECU? Alternatively maybe the sensor itself has failed or broken?

On another note I know those crank sensors sometimes have to calibrate themselves before working 100% so a fresh start up after disconnecting the batteries may do the trick! Good luck