Cam sensor trigger wheel torque + cam sensor resistance - 2002 XC70

[jonesg]

From the video, they infer that one of the voltages should be around 5V and the other 12V. In this case, Pin # is just under 5V (4.9 ish) and pin # 2 is the ground. Pin 2 and 3 connected give around 5V also? Is this correct for a Volvo?

How do you probe the back of the connector? Volvo has sealed the pins with a rubberised material. Do I have to find a way of trying to push the tips of my probes through there, or can I try pushing a sewing pin into it?

Neil.

piercing probes, or T pins , and liquid elec tape to seal the holes.

[jonesg]

From the video, they infer that one of the voltages should be around 5V and the other 12V. In this case, Pin # is just under 5V (4.9 ish) and pin # 2 is the ground. Pin 2 and 3 connected give around 5V also? Is this correct for a Volvo?

How do you probe the back of the connector? Volvo has sealed the pins with a rubberised material. Do I have to find a way of trying to push the tips of my probes through there, or can I try pushing a sewing pin into it?

Neil.

black , blue , red.
blue is signal, usually around 5v max.

from vida AllData ,

"The sensor, which is a magnetic resistor with a permanent magnet, is grounded in the control module and supplied with 5 V from the control module. When one of the teeth on the camshaft pulse wheel passes the camshaft position (CMP) sensor, a signal is transmitted to the control module from the camshaft position (CMP) sensor. The signal varies between 0 - 1 V and is low when a flank passes the camshaft position (CMP) sensor."

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i think the engine needs to be idling, either way theres no mention of 12v.
i would assume its correct considering its coming from the ecm.
all 3 wires come from the ecm, so i wouldn't expect to see 12v but i'm just going on intuition.
i think vida should be able to test it.

conversely, if you do the same test i did today and get the same result that confirms a known good. mine runs good.
either way you at least have a diagnostic approach..... if you can get it running.

[scot850]

Well the car did run (roughly) before I started!

I was just going by the video of the 2 guys testing the car. Problem is, like you say there may be only one way to test this and that is with Vida. I just wish the wiring diagrams gave you the simple information like they used to. Like +ve or -ve, gnd, +12V, +5V or whatever. Canbus is hard enough to work with as it is!

The pins are Red/white, Black and Blue/Black which ties up with what you have said. Both Blue/Black and Red/White were at 5V what I don't know is what should they be? Both 5V if so then all is good? If you check the video at around 2.45 minutes they mention one wire is fed from the battery voltage (12V), one is ground and the third is fed 5V from the ECM.

I will have to look at what you mean by T-pins and piercing probes. The probes I have have fairly sharp points but I was unsure about damaging the insulation to test them (I'm not electrical background, but know enough to be dangerous!!).

What the guys showed in the video was re-fitting the cam sensor into the connector, switching the ignition on to 2 and waiving a piece of metal in front of the sensor and it should drop to 0V.

Thanks again.

Neil.

[jonesg]

Well the car did run (roughly) before I started!

I was just going by the video of the 2 guys testing the car. Problem is, like you say there may be only one way to test this and that is with Vida. I just wish the wiring diagrams gave you the simple information like they used to. Like +ve or -ve, gnd, +12V, +5V or whatever. Canbus is hard enough to work with as it is!

The pins are Red/white, Black and Blue/Black which ties up with what you have said. Both Blue/Black and Red/White were at 5V what I don't know is what should they be? Both 5V if so then all is good? If you check the video at around 2.45 minutes they mention one wire is fed from the battery voltage (12V), one is ground and the third is fed 5V from the ECM.

I will have to look at what you mean by T-pins and piercing probes. The probes I have have fairly sharp points but I was unsure about damaging the insulation to test them (I'm not electrical background, but know enough to be dangerous!!).

What the guys showed in the video was re-fitting the cam sensor into the connector, switching the ignition on to 2 and waiving a piece of metal in front of the sensor and it should drop to 0V.

Thanks again.

Neil.

the video isn't a volvo, the benefit of volvo design is stray 12v current can't get in the ecm.
so don't feed 12v to that plug, it will fry the ecm because the circuit isn't diode protected.
i use a lisle test light that only allows 500 millivolts to pass, its computer safe.
cheap piercing probe tend to fall apart or bend, decent ones are $23. designed for one hand operation in very tight spaces.

https://www.amazon.com/Power-Probe-PPTK ... B077SFMJPX

https://www.amazon.com/Permatex-85120-L ... r=1-3&th=1

[jonesg]

i have this cheap $17 set of backprobes , sharp as a needle. from amazon
its better to use these , piercing probes reserved for situations where you cant access with both hands .

[jonesg]

i get .04 v on both sides, its very low, maybe it has to be running, i'll try later.

[scot850]

I had the ignition at Pos II and was getting 5V on the 2 outer (#1 and #3) pins with the connector disconnected. I have done what you have shown and upgraded with an Amazon purchase of pin probes and a better set of probes. I already have the liquid tape for house and car repairs, but thanks for the links anyway!

The Amazon delivery is due later today so hopefully I can get back to this today. I now plan to get my son's help to operate the ignition key so I can watch what the original and my loaner TB's are doing when the ignition is switched on and off. The original sounds like a bag of bolts and graunches really badly. I believe these have plastic gears that a prone to failure. I need to confirm if the loaner TB is from a similar spec'd engine. I also need to the adaptions. I have to disconnect the battery anyways to pull the ECU/TCU for cleaning. I'll touch the +ve and -ve cables to clear the system. I will do the adaptions later with Vida.

Thanks again!

Neil.

[scot850]

OK. I'll add pictures later. I connected the cam sensor up and received my Amazon needle probes this afternoon. With help from my son, (I needed about 3-4 hands to do this ) I tried probing the connector through the seals. I had to move the needles around to find a connection.

For Pins #1 and #2 I get approx. 5V. For pins #2 and #3 I get around 0.25V.

Pin #1 is Red/White, Pin #2 is Black and Pin #3 is Black/Blue.

I was able (with the extra hands available) with the pins #1 and #2 connected the 5V goes to 0V when you wave a piece of metal near the end of the sensor. When you try #2 and #3 it went from around 0.25V to 5V.

So not sure what this is telling me?? Without the sensor fitted I was getting 5V on Pins #1 and #3.

Neil.

[jonesg]

OK. I'll add pictures later. I connected the cam sensor up and received my Amazon needle probes this afternoon. With help from my son, (I needed about 3-4 hands to do this ) I tried probing the connector through the seals. I had to move the needles around to find a connection.

For Pins #1 and #2 I get approx. 5V. For pins #2 and #3 I get around 0.25V.

Pin #1 is Red/White, Pin #2 is Black and Pin #3 is Black/Blue.

I was able (with the extra hands available) with the pins #1 and #2 connected the 5V goes to 0V when you wave a piece of metal near the end of the sensor. When you try #2 and #3 it went from around 0.25V to 5V.

So not sure what this is telling me?? Without the sensor fitted I was getting 5V on Pins #1 and #3.

Neil.

i would call it good unless theres some reason not to, ?
ecm-643A is a timing code, not a timing sensor code.

vida says,

ecm-643a
Possible source

Signal too high
- Poor oil quality
- Incorrectly adjusted camshafts
- The timing gear belt has jumped off the cogs
- Defective reset valve
- Mechanical fault in the variable valve timing (VVT) unit.

Signal too low
- Poor oil quality
- Incorrectly adjusted camshafts
- The timing gear belt has jumped off the cogs.

if the cams are in time it is usually poor oil quality .
thats why i asked about the oil change, mine disappeared with just an oil change.
if oil/filter change doesn't fix it then its usually the oil pan Orings , they distort and block oil pressure to the vvt solenoid, if the solenoid is lagging it sets the code 643a.

heres what an old oring does, swells up and distorts the oil passage on the oil pan lip.

[scot850]

This is the code. I removed it and it came straight back:

The failure code is : P0016 or (643A) ECM-643A : Cam Position - exhaust: Signal too low

This is where the thread started. I think it would appear to be ok. I will re-test on Monday when I hope to get the new aftermarket sensor for comparison and update here.

The other point I realized I had not picked up from the video is the car they were testing on had 2 cam position sensors, one per/bank. Perhaps that is why I am seeing the 2 x 5V readings as my car has only one sensor?

Neil.