How to test a cam sensor with a voltmeter

[@terreckk]

this video saved my life

[@ScannerDanner]

Mitchell has a program for a "day pass" if you want to call it that. I'm not sure the web link off hand but I know they have it.

[@nickayivor8432]

KNOWLEDGEABLE Sir ScannerDanner Thanks 👍 Sir ScannerDanner From Nick Ayivor from London England UK 🇬🇧

[@Graffik93]

On a hall effect cam sensor is the voltage suppose to drop when the cam magnet passes in front of the sensor or is it suppose to jump to 5v? PLEASE ANSWER.

[@nickoglock]

I replaced one of these in a 4.0 jeep today, the odd thing to me was I I plugged the good one In and ran a hose clamp through it , and it didn't change cam count, but it worked once installed.

[@MM0SDK]

i that little rod or probe a can opener thingy that you sometimes get on corned beef and stuff. If it is.... bloody brilliant idea. love yer vids mate. All the best to ya.

[@japsmechanic7627]

Can i use multimeter put it to amps?

[@mattpendley8057]

Great video dude! Very well explained. $10k Verus does make it easier though doesn't it!

[@mrgalea100]

So the dvom is connected to sensor signal and battery ground?

[@ScannerDanner]

yes sir

[@ScannerDanner]

It is possible that there was a cam or crank sensor driveplate/trigger wheel change up in the model years. Search my 2004 Dodge Caravan video. This could cause this condition. Are you a member of iATN? You could search their waveform library. Or do you have a scope that you could give me the waveforms from?

[@danpettis1675]

ScannerDanner do I need every bit of the 5v .I measured 4.92. Is the pcm not putting out enough voltage? Thank you

[@troyjohnson5126]

Low voltage on ABS system. Hydraulic Pump is there a video.

[@mattpendley8057]

That's actually a back-probe pin. I've seen the long straight pins used for sewing used for this as well.

[@dodgeplow]

That's a T-pin, the type of which has existed long before there was a need for back-probing.

[@inmyexpression19]

Yes they are used for sewing and auto mechanics took them

[@ahill007ny]

Hey Paul I have a 2001 Dodge Intrepid 3.5 that will only run with the Cam unplugged. The owner has replaced both Cam and Crank sensors. I checked the wiring to the Cam, 8.91 on supply 4.96 volts on signal unplugged 0.06 plugged in and ground is 0.02. When I crank with the Cam plugged in the tach will rise to 1500 rpm. Also when I plug the cam in the ASD will click and fuel pump will do its prime then everything is silent. What are the chances that the timing has jumped? Thanks

[@mrgalea100]

So you put one lead from the scope to the crank sensor signal wire and another lead on battery ground?

[@ScannerDanner]

yes sir

[@hddm3]

where can you get wiring diagrams if you dont have mitchell or alldata

[@inmyexpression19]

What would happen if I put the black test lead on the black ground wire instead of battery ground?

[@ScannerDanner]

As long as the sensor ground is good, it would read the same. If your sensor ground was open, you'd read 0 v leading you to believe you have no 5v ref, but I'm actuality you also have 5v on the sensor ground. This is why I chose battery ground first

[@inmyexpression19]

@@ScannerDanner ok thank you very much! Good stuff

[@shameelali2549]

Where do you get that back probe Dan?

[@pabloarevalodelaguila8767]

Muy bueno.

[@OldePhart]

in know this was a long time ago, but I have a P1391 error and since that doesn't specify which sensor is bad so I am using a 2 trace scope to watch both, It would be interesting to see both signals together and their relationship. (could see a broken flywheel tooth too perhaps). Just a thought.

[@ScannerDannerPremium]

I have a video on that code. It was on a 2004 caravan. The P1391 is a cam crank correlation code, and is usually not from a bad sensor.

[@OldePhart]

I looked through the list...how did I miss that? I'll look again.

[@OldePhart]

ScannerDanner Premium please point me to that video. I can't locate it. One more thing if I may, I'm using a Fluke scopemeter to look at these signals and i am not seeing a good square wave on either one yet the engine runs fine. If these are Hall effect devices I would expect a nice pulse shape, if just a coils I would expect a sine. Does the scope you are using perform any signal shaping?

[@ScannerDanner]

2004 Chrysler 3.3L Cam Sensor Problem (P0344, P0016) I thought this had a P1391 code but it did not. As for the scope pattern, you should definitely be seeing clean square wave patterns. Try increasing your sample rate if you can or reducing your time base. Also if there is a lot of noise use the sensor ground instead of battery ground for your scope

[@OldePhart]

ScannerDanner I have the square wave now but not the clean one I would like. I have almost a volt of high freq noise on the signal from the cam sensor that is not present on the crank sensor. I suspect HV ignition is crosstalking but not sure. Repalce cam sensor and have same issue. Lost a scope lead in the belt so until I get my other scope from work I can't compare timing between them but I would guess its possible that the PCM is seeing that noise and interpreting it as real, and throwing a loss of sync code. All I have for a scanner is an old Snap on model that just says Current Sync = Lost. I know I'm close, just gotta find that last nugget. How can I verify the timing between these two sensors using only the scope patterns?

[@christophermix6845]

My 2000 Silverado with the multi meter set on 200m reads 17.0 then when cranking spikes to 19.3 and then stays around 16.7 then when i stop cranking Spikes to 24.8 then back to 17.0. isn't that way to high? I have my negative lead on the negative battery and positive connected to the cam signal. The cam sensor is not connected. I have had a warm hard start the last 2 years. If i let the truck sit for 5-30minutes after driving then try to restart it, it won't start unless I hold the gas pedal down. The truck fires Right up on cold starts and after sitting 1-2hrs after driving. This all started happening after I replaced the cam sensor connector, but im getting signal through it on my multimeter. Ive tried everything, fuel pump and every sensor, a different PCM, cannot figure out whats wrong. I literally want to drive the truck in a ditch lol. Please help! No codes, but for some reason it is trying to flood itself on warm starts and had a body shop use a scanner said everything looked good besides it runs really rich at idle. They didn't notice anything that could be causing the hard start.

[@ScannerDanner]

200m? As in 200 millivolts? 200m wouldn't be the correct scale on a voltmeter, if that was even the voltmeter

[@christophermix6845]

@@ScannerDanner or maybe it's a multimeter? I had it on volts (the straight line on top and dots on the bottom symbol) I don't know squat about electrical stuff obviously. I tried volt~setting (wavy line symbol)and got 0 with the key on, then when cranking it would get up to 5.3, shouldn't there be a signal with the key on as well? I'm stumped on the issue though and very frustrating. Doesn't make sense. As it never throws a code for anything. And I've made sure the connector is wired properly.

[@ScannerDanner]

​@christophermix6845 yeah, thats 200 millivolts, wrong scale. You should be set on most likely a 20v scale for every test you're trying to do

[@christophermix6845]

@@ScannerDanner gotcha. Any ideas on my issue?

[@ScannerDanner]

​@@christophermix6845you're barking up the wrong tree with the crank sensor. Focus on your fuel system. This sounds like a classic leaking fuel pressure regulator diaphragm