Put a new crank sensor in and had signal but no spark. Found out the coil pigtail was bad so replaced it. Now a month later I have no signal from crank sensor again. Its got good power and ground but only about .2 v of signal. And I did an inductive test an got nothing. Anyone know what it should be reading on the inductive test?? Please I need her back driving again

 

I guess i'm not sure what an "inductive" test is? The a/c output? The only surefire way to check a crank sensor is with a labscope

 

if you unplug the connector at the crank sensor you should have a 5 volt refrence with the key on engine off.if you have .2 of a volt ,it sounds like a bad wire or ecm.as cleveland metioned the best way to check is to use a labscope to see what kind of signal the sensor is putting out.

 

I meant I ohm tested the sensor when I said inductive test. I got a bunch of schematics could I ohm test the wire from the computer to the sensor to see if it's bad? I'm not good with electrical. Its my weakest piont. Also the passlock sensor is putting out .2 volts also. Haven't had the time to see if other sensor are the same. But if they were what would cause that? A bad bcm or ecm?

 

you have .2 signal or at the 5v ref? yes you could just do continuity checks from end to end on each wire and if you only have .2v at places you should have power supplies I'd be checking the voltage in and out of the ignition switch.

 

Sorry I think I mistyped what I was tryin to say. It has a good ground an power but only puts out .2v of signal. And when I crank it the power wire drops down to about 8 or 9 volts. I think it's a short to ground but could it also be my battery or a bad ecm?

 

are you checking for a/c voltage while cranking backprobing the signal wire? If you have the sensor unhooked and you're testing the signal wire at the connector you won't have anything

 

It's plugged in but I have my multimeter on dc. As I have always had it and gotten 5 v. I had this problem a few months agai and I found the passlock signal wire had resistance and the computer wasn't seeing the right signal therefore no spark. I replaced that wire and and got signal at crank sensor and spark again. It still wouldn't start cuz I had flooded motor from cranking so much. After I fixed that issue I tried starting an nothing so I backtracked my steps and found no signal at crank sensor again. Would the supply voltage dropping to 8v when cranking effect the signal output?

 

what vehicle is this? Are you saying you have a constant 5v dc on the signal wire at the crank sensor? If that's the case you have a short somewhere or I'm just not following you correctly. Its 3 wires right? 5v ref, low ref and signal?


Yes if you're only getting 8v at the battery cranking your battery needs charged/tested

 

2003 Chevy Silverado 1500 4.3l. Three wires I thought on e was power one was a ground and the the signal wire. I'll have to go out tomorrow and double check this. One wire I get good ground another I get 12 volts and another which I though was a 5v signal to computer I get .2v at. I'm getting 12.3 at battery. I know that's ok. I just don't understand why the ref wire is showing the same as battery if your sayin it is supposed to be 5v