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Discussion Starter · #1 ·
Sorry was not trying to start another entry in the forums but I can not seem to figure out a way to change the title.I have the post about the 2002 s60 starting problems.
The car is the non turbo automatic 2.4 liter.
I have searched this site for information about testing the camshaft sensor and found a generic link to testing the 3 wire ones and it says one pin should have 12volts and one should have 5volts well mine has 5 volts at both.
Was wondering if anyone with the same style sensor as mine (3 wire pull off style plug on the sensor) could see if they get 5 volts on both power pins 1 and 3 ? and if it is not to much trouble if the voltage fluctuates on pin 1 when turning over mine spikes around 1.8 and 3.6 volts when cranking.
Any help would be greatly appreciated this car has been driving me crazy trying to figure it out for the last 2 months of why it will not start.And knowing for sure of what the voltage on the cam sensor should be will help me get past it so i can move on to something else.thanks for your time and expertise.
 

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Never had to test one on our cars but the cam sensors are Hall effect sensors. 3 wire sensor with a 5v Ref, Signal Wire, and a Sensor ground.

What seems to have led you to the cam sensor anyhow?

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Discussion Starter · #3 · (Edited)
First thanks for the response and your time.Should both wires (pins 1 and 3) have 5 volts ? minus the ground in the center (pin 2) mine does with the key on.I am having a crank but no start problem I have the thread just below this one.But for a quick rundown I removed the plugs they all fire once then stop even when it is still turning over,great fuel pressure,great compression,no security or immobilizer warnings,great charge,turns over perfect,all electrical items work (brights,dash,windows,alarm etc etc) but will not keep firing.
 

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Have you looked at the crank sensor? If you have a cheap code reader with the capability to read live data. Check for an increase in rpm value while cranking. If the value stays at zero, you have a problem!

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Discussion Starter · #5 · (Edited)
I do not have one at the moment but my rpm on the dash does move up to around 600 rpm and holds there while it is cranking.I am going to order one of those vida dice volvo knockoff scanners here soon.I did check the crankshaft sensor the best I could with a volt meter it has 130ohms and produces .2 volts when turning over.
 

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I think I may have missed a crucial part in your previous post. You're a saying you have 5v on both the vref and signal wire ckts for the cam sensor? Do you have a wiring diagram handy?

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Is the signal voltage exactly the same as the vref is what I'm asking

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Discussion Starter · #8 · (Edited)
Yes there is 5 volts on both with the key on and the 5 volts on pin 1 fluctuate when its turning over anywhere from 1.8 to 3.2 volts and pin 3 stays at a solid 5 volts.I do not have a diagram at the moment but I do have Vida 2014 on my computer just trying to figure out how to find the wiring diagrams on it.
 

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It should, as far as I know, cycle between 5v and 0v on the signal wire as hall effect sensors usually produce a DC digital output unless it's one with a DC analog output. If I have time today I'll test mine and see what it should be as I have the exact same car as you.

For S&G's, try unplugging the sensor and measure voltages at the harness side. Make sure you have a solid 5VREF, a good ground, and a kosher signal. Just read voltage for the VREF, measure continuity + resistance value for the ground ckt, and make sure you do not have any voltage or shorts on the signal (measure continuity between the signal and VREF)



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Discussion Starter · #10 ·
Ok thanks again for the quick reply's I appreciate you taking time to try and help me out.Ok when I remove the harness from the sensor there is 5 volts on the ref side and 5 volts on the signal side ground test good.I included a image of what my sensor looks like.
 

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That seems to be an issue right there. Check continuity between signal and VREF. Sounds like you have a short

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Discussion Starter · #13 ·
Ok I am new to testing the continuity but with what I gathered from online is to set my ohm meter to its lowest setting (200ohms) I then checked the signal and ref together and it was not showing anything on my meter which I assume means they are not shorting together if I did that right.When I checked the ground with one probe to the block and one to the ground (pin 2) it showed 0.05 which I assume means it is a complete circuit.
 

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Yea some meters have a separate "Continuity" setting. However, a resistance reading (as long as the ckt is isolated) is also acceptable. But you are correct that if the VREF and signal were shorted, you would have a fairly low resistance value. Im not sure what kind of Meter you have but I would try all of the resistance settings measuring between VREF and signal. The fact that it is showing 5v on the signal while disconnected from the sensor worries me.

From what it looks like, you have measured correctly however I don't think meter has an auto ranging function and since you are testing open ckt voltage when you disconnect from the sensor, there could still be any amount of resistance in the harness between the two wires. Your reading on the ground ckt is all good as well @ 50 milliohms.

My recommendation would be to leave the leads on your meter connected to the signal and VREF ckts and switch between your time distance settings on your meter waiting a few seconds in between setting changes.

Now, for the record, in going off of my basic ckt functionality knowledge in trying to help you out. If for whatever reason, these cars have some sort of adaptive strategy and it is sending the 5v through the signal as a form of "self check" then that could explain this entire scenario and the diagnosis will have to go in other direction.

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Discussion Starter · #15 · (Edited)
Ok so I turned the ohm meter all the way to 20k I will then see 3.29 testing the ref and signal together but I also get 1.4 if I probe only the signal or VREF with the other probe going to the block.Here is a picture of the same meter I have.
 

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3.29kohms sounds like it's just reading the resistance through the ecm. If it was shorted, it would be much lower than that. It seems like it's not shorted so it must have some sort of strategy to check for open ckts by sending voltage through the ckt.

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Discussion Starter · #17 · (Edited)
Next week I will be ordering the Vida Dice from Ebay but who knows how long before it gets here since it is coming from china,I am hoping with it I will have better luck trying to figure out whats going on, I was thinking I was on to something with the voltage on the Camshaft Sensor.Still curious if the voltage is suppose to fluctuate on pin 1 when turning over like it does ?
This is one of the other reasons I was suspect of the camshaft sensor here is a article I found with a car having the same issues:


Vehicle Application:
1998 Volvo S70 2.4L, Vin 55, Eng Des B5254S
Customer Concern:
No start. There is one spark right away but nothing after that. There is no injector pulse either.
Tests/Procedures:
1. Test the signals at the Cam Position (CMP) sensor. The ground circuit connects to the Brown/Black wire at pin 1.

2. The CMP sensor signal circuit connects to the Blue/Yellow wire at pin 2. It should show a 0-5v digital square wave signal while cranking and at idle speed.

3. The CMP battery power circuit connects to the Yellow/Red wire at pin 3. It should read 12v at key on or engine running.

4. If all of the circuits are OK, but there is no signal, replace the CMP sensor.

5. To check the crank sensor, find the connector for it. The sensor is located in the top of the transmission bell housing, so just follow it back to the connector. It has two wires, pin 1 is a Blue wire, and pin 2 is a Red/Black wire. With a Digital Volt Ohm Meter (DVOM) set to ohms, unplug the connector, and do a continuity test through the sensor between pins 1 and 2. It should ohm about 300 ohms. Then switch the meter to A/C voltage and crank the engine. It should produce 0.8 of A/C voltage. The spec. at idle is 1.5 volts A/C. Cranking speed can affect the test, so have a fully charged battery when checking it.
Potential Causes:
Defective Camshaft Position (CMP) Sensor
Crankshaft Position (CKP) Sensor
Open Wiring Harness
Shorted Wiring Harness

But the harness on this one is different because the ground is on pin 1 and mine is on pin 2 so I assume this one may work a little different having the 12v on pin 3 that's why I was thinking if someone had the same one as me they can see if they have 12v on either pin.
 

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Have 12v while cranking or just KOEO?

Sorry for the late reply. Had to run a few errands.

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Alright no problem. I will disconnect my cam sensor harness when it gets light outside and see what my voltages are with the key on to get a baseline. I'll have to figure something out as far as backprobing though. Don't have any old school T-pins anymore

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