How to test a cam sensor with a voltmeter

The tests shown in this video apply to camshaft, crankshaft and vehicle speed sensors on ALL Chrysler models, in all production years. The vehicle being tested is a 1997 Jeep with a 4.0L engine.
Chrysler has changed very little in regards to their hall effect sensors throughout the years. Older systems used an 8-9v reference circuit (power supply), where the newer systems use 5v. And with all of them, the signal circuit is a 5v pull-down design.

Engine Performance Diagnostics chapter 21 pages 20-29

Tests shown
- how to check a cam sensor with a voltmeter
- what does an on/off digital signal look like on a voltmeter
- how to check the 5v reference and ground to the sensor
- how to perform a bypass test
- how to verify signal circuit integrity
Tools used
- digital multimeter
- jumper wire
- backprobing pins
- incandescent test light
- scan tool

Related videos
- 1997 Dodge Neon no start, crank sensor problems
- How to test a crank sensor (Chrysler Dodge Jeep)
- How to test a crank sensor with a voltmeter (All Chrysler models)
- 2003 Chrysler-Dodge 3 8L No Start (faulty crank sensor)

Playlist
(Chapter 21) Ignition inputs, cam and crank

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[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.

[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.

[Graffik]

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.

[nickayivor]

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

[MMSDK]

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.

[troyjohnson]

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

[mrgalea]

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

[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?

[shameelali]

Where do you get that back probe Dan?

[mattpendley]

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

[ahillny]

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

[hddm]

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

[mrgalea]

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

[mattpendley]

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

[inmyexpression]

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

[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. 

[christophermix]

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.