General How to check a crankshaft sensor?
- Thread starter Stark
- Start date
Currently reading:
General How to check a crankshaft sensor?
You want to measure its resistance but the only true reliable way is when the sensor is working,in this case you would need a oscilliscope.
Careful what you do with the multimeter,measuring resistance with ECU connected can damage it.Maybe leave this one to dealer??
Careful what you do with the multimeter,measuring resistance with ECU connected can damage it.Maybe leave this one to dealer??
the CPS (or rpm & tdc sensor as fiat call it) can be tested in 2 ways.
the choice is either:
disconnect the sensor's wiring connector and then test using the sensor's pins.
disconnect the ecu and then test using the ecu connector's pins
for the sake of accuracy it is often best to test the sensor using the sensor's pins. however the advantage of testing from the ecu connector is that you also get to test the wiring all the way back to the ecu, and it is often easier to get access to the ecu's connector.
the choice is yours.
if you decide to test by accessing the sensor directly, you need to measure the resistance across pins 1 & 2. pin2 is the centre of the 3 pins. pin 1 is the right hand pin when looking at the sensor (so that the top is the side which had the connector's push clip on)
if you test using the ecu's connector you need to measure resistance across connector pins 30 & 49.
using either method, you should see a resistance of 575-750ohms.
another test you can do is a gap check. the distance between the sensor and the phonic wheel (the big toothed wheel) should be 1mm between the sensor's face and the top of the teeth on the phonic wheel. the range allowed is 0.5-1.5mm but you really want it to be as close as possible to 1mm. you can check this gap using a feeler gauge, and adjust if neccessary by loosening the sensor and adjusting its position. this must be done very carefully to ensure the sensor remains perfectly in line with the tangent of the phonic wheel.
how on earth can you test the sensor's resistance with the ecu connected to the sensor?
the choice is either:
disconnect the sensor's wiring connector and then test using the sensor's pins.
disconnect the ecu and then test using the ecu connector's pins
for the sake of accuracy it is often best to test the sensor using the sensor's pins. however the advantage of testing from the ecu connector is that you also get to test the wiring all the way back to the ecu, and it is often easier to get access to the ecu's connector.
the choice is yours.
if you decide to test by accessing the sensor directly, you need to measure the resistance across pins 1 & 2. pin2 is the centre of the 3 pins. pin 1 is the right hand pin when looking at the sensor (so that the top is the side which had the connector's push clip on)
if you test using the ecu's connector you need to measure resistance across connector pins 30 & 49.
using either method, you should see a resistance of 575-750ohms.
another test you can do is a gap check. the distance between the sensor and the phonic wheel (the big toothed wheel) should be 1mm between the sensor's face and the top of the teeth on the phonic wheel. the range allowed is 0.5-1.5mm but you really want it to be as close as possible to 1mm. you can check this gap using a feeler gauge, and adjust if neccessary by loosening the sensor and adjusting its position. this must be done very carefully to ensure the sensor remains perfectly in line with the tangent of the phonic wheel.
how on earth can you test the sensor's resistance with the ecu connected to the sensor?
