how to test a crank position sensor
#12
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#13
You can use a ohm meter to check resistance with the sensor unplugged, it is a coiled magnet and b+ to sensor ground has specs to produce a correct signal, b+ to sensor base is a short to ground test. It would be how helpful a dealership would be to give the specs for the resistance test.
The paperclip tests give voltage output numbers but still need to know the out of range specs of that test.
The paperclip tests give voltage output numbers but still need to know the out of range specs of that test.
#14
TONS OF BAD INFO ON THIS THREAD! NONE OF WHAT WAS MENTIONED SO FAR IS CORRECT.
1. there is no batt voltage to the CKP, period
2. the pulse is not a pulse but a constant a/c voltage PRODUCED by the ckp sensor itself
3. the drop in a/c voltage caused by the missing tooth tells the ecm what part of the stoke the engine is on, and the slow down of the crank (upon compression), and lower a/c voltage tells the ecm what phase the engine is on.
4. the only way to test the ckp, is to UNPLUG it from the ecm, put a multimeter on the 2 wires, (R/B and B) and crank the engine. it should show 1-5 VA/C.
5. this is hit or miss, some ckp show good when they are not, but if it shows bad, it is.
1. there is no batt voltage to the CKP, period
2. the pulse is not a pulse but a constant a/c voltage PRODUCED by the ckp sensor itself
3. the drop in a/c voltage caused by the missing tooth tells the ecm what part of the stoke the engine is on, and the slow down of the crank (upon compression), and lower a/c voltage tells the ecm what phase the engine is on.
4. the only way to test the ckp, is to UNPLUG it from the ecm, put a multimeter on the 2 wires, (R/B and B) and crank the engine. it should show 1-5 VA/C.
5. this is hit or miss, some ckp show good when they are not, but if it shows bad, it is.
The following 5 users liked this post by jmetro:
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#15
TONS OF BAD INFO ON THIS THREAD! NONE OF WHAT WAS MENTIONED SO FAR IS CORRECT.
1. there is no batt voltage to the CKP, period
2. the pulse is not a pulse but a constant a/c voltage PRODUCED by the ckp sensor itself
3. the drop in a/c voltage caused by the missing tooth tells the ecm what part of the stoke the engine is on, and the slow down of the crank (upon compression), and lower a/c voltage tells the ecm what phase the engine is on.
4. the only way to test the ckp, is to UNPLUG it from the ecm, put a multimeter on the 2 wires, (R/B and B) and crank the engine. it should show 1-5 VA/C.
5. this is hit or miss, some ckp show good when they are not, but if it shows bad, it is.
1. there is no batt voltage to the CKP, period
2. the pulse is not a pulse but a constant a/c voltage PRODUCED by the ckp sensor itself
3. the drop in a/c voltage caused by the missing tooth tells the ecm what part of the stoke the engine is on, and the slow down of the crank (upon compression), and lower a/c voltage tells the ecm what phase the engine is on.
4. the only way to test the ckp, is to UNPLUG it from the ecm, put a multimeter on the 2 wires, (R/B and B) and crank the engine. it should show 1-5 VA/C.
5. this is hit or miss, some ckp show good when they are not, but if it shows bad, it is.
thanks for the information.
#16
Join Date: Mar 2007
Location: Woodstock, Ont , Can
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Angel Espinoza (06-02-2020)
#18
#19
don't need a scope
Go to Radio shack, buy a 5 volt LED for $2.00, time response is fast so you can see the pulsing, works great - a lot chaeper than an oscilloscope..Mike
#20
This is brilliant. If you happen to have a camshaft position sensor (My 2000 FLHR-EFI does) this method works for it too. It can be difficult to hold a multi-meter and try to read a voltage. Get the 5 volt led and solder a short length of wire (pigtail) onto each terminal, then a small alligator clip on each of the other 2 ends. Unplug the ckp harness, connect the alligator clips and viola'. I also use this method to ck injector harnesses.