Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
96 Dodge Grand Caravan Crankshaft Position Sensor Issue
Hi all,
I've been struggling with this for a while.
The car cranks, no start, no spark.
I do the diagnostic test via the PCM and it says no crankshaft signal.
I buy a new crankshaft position sensor, put it in, it works, car runs.
I drive the car for a little bit, park it, come back 30 minutes later, won't start.
I have about 4 other CKP sensors that i've put in and presumably they all got fried.
I literally bought the newest sensor yesterday and after not more than 4 minutes of driving it's already bad?
I don't have any meaningful way of testing the wiring besides checking for continuity between the PCM pinouts and the sensor. I can't tell if it's getting 8 volts as it's supposed to because I don't have a helper, but every time I put in a new sensor it works so I can only assume it works.
My scope doesn't come in until tomorrow but this is a real head scratcher- how the hell can they all keep breaking?
Secondly, how could the sensor have broken in 20 minutes between driving perfectly fine, parking it, and sitting there (off)
This is a 3 wire hall effect sensor, so you do not need a second person to confirm the 8 volts supply. With the ignition on and the sensor disconnected you should see 8 volts on the feed wire. When connecting the sensor the 8 volts should maintain while the ignition stays on.
When measuring the signal wire you should get a reading that switches from 5 volts to 0 volts back and forth while turning the crankshaft.
Once you got your scope you`d want to look what's happening to the actual signal in detail, watch out for voltage spikes etc.
Make sure there is no problem caused by EMF like leaking secondary igniton (ht-cables).
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
Thanks, that confirmation of the 8v supply is very helpful.
Apparently i'm only getting like 0.387V with the key on after further testing.
Interestingly my ASD relay also does not seem to be powering the B+ terminal on my ignition coil anymore, which it was just a few hours ago....
I need to refer to my wiring diagram to see what all these have in common.
I'm confused because this usually gets fixed with a new sensor yet somehow seems like something deeper, a wiring problem. Ill report back with more hopefully soon
Topic Author
