Camshaft position sensor

[ragrim]

I was at holden yesterday getting my suspension looked at and they put the computer on to check my engine codes and apparently my computer is reporting no camshaft position sensor. Holden couldnt tell me why i was getting that error, either the sensor was bung or not plugged in and they couldnt tell me where it is. i was wondering if anyone could tell me where this sensor is, and also could this have something to do with the idle issues i have been having, high and low idles at random times.

Cheers

[VrWagz1]

depends if you have a V6 oR V8 and i assume we talking about the vs??. I'm guessing v8 because v6 only has a crank angle sensor, where the v8 has a hall effect sensor driven by the back of the cam. The sensor is inside the base of the dizzy, have fun with that.

[ragrim]

its a V6, i have a book for a VS here and it has a cam position sensor aswell, my VR V6 sensor is in the same place as the VS, i unplugged it and made no differance to the car, so i dunno what its ment to do.

[VrWagz1]

If is a v6 i cant really comment further as i dont really know a great deal about them, as far as i was aware they only had a cas down on the harmonic balance

[ragrim]

i found the cam shaft position sensor just undr the water pump to the left. ill clean the wiring and plug and see if it helps.

[Brett_jjj]

VS V6 has a cam position sensor.If the sensor itself is replaced and it still throws up an error code,theres a magnet in the camshaft drive sprocket that triggers the sensor as it passes the sensor pickup.Ive seen this magnet (which is encased in a plastic cage type thing that holds it in the sprocket)come out of the hole on the sprocket.We removed the timing cover and the magnet was stuck to the block behind the timing chain luckily.It a fairly strong magnet.Just had to buy a new magnet and install it.It cost around $80 from holden.Ive seen some USA websites where they glue the magnet in place so it cant come out,so it probably happens from time to time.This one we fixed wasnt glued in but its still going stong today around 100,000 k's after.

[ragrim]

what bothers me though is the ecu is throwing out an error yet the car is running, its not running perfectly but it doesnt stall or blow smoke. i just have some irratic idles at times.

[Brett_jjj]

This engine still ran,it just idled roughly and would sometimes stall while idling.And it was just generally not running 100%.But still ran and was drivable.

[Brett_jjj]

---Checking error codes VR/VS (Revised)---If you dont know how to,heres a link to a thread that shows you how to check your own error codes without having to go to holden.Error code 48 is no signal from the cam angle sensor.

[VrWagz1]

You got to remember an ECU controls the car. So generally they can somtimes run a car minus a non-critical sensor, or the sensor may be to fine tune the running of the car, and as such the car will run with a rooted sensor albeit a bit crappy.
If the vs still has the cas aswell, theres no reason why the ecu wouldnt be able to do algorithms based on the cas position to keep it putting along.

[ragrim]

i did check the engine codes and all i get is 12 31 and 35, i assume it can only hold 3 codes and thats why i never knew about the cam sensor.

[Brett_jjj]

Code 12 is shown 3 times repeated over and over to show no logged error codes.Or its also used to show the start and end of the error test.Code 31 is to do with the BCM (Body Control Module) not returning a signal to the ECU for the immobiliser.It seems to be a fairly common error to get and causes a 2 second delay before the engine cranks when the ignition key is turned to start.Code 35 is The IAC (Idle Air control) valve not being able to control the idle speed.The ECU can hold more than 3 error codes.

[ragrim]

well i get 12 12 12, 31 31 31, 35 35 35.

As i mention in another post about my idle i replaced my IAC and it seems to have semi fixed my idle issues, i was idling at 1500 rpm before now it idles from 500-1000 depending on what mood its in, i reset the computer and its still giving the same errors. im wondering if the cam sensor is also having an affect on my idle which is therefore still throwing out a code 35

[Brett_jjj]

im wondering if the cam sensor is also having an affect on my idle which is therefore still throwing out a code 35

It could be.It effects the idle pretty badly with no cam angle signal.

[Cheap6]

No cam signal pulls the plug (almost literally) on the sequential operation of the fuel injection, which goes back to VN-VP style batch fire mode i.e. fires all the injectors together instead of in firing order.

Definitely worth looking for the magnet; you should be able to see it through the hole where the cam sensor sits.

If you want to check the wiring, try:

5V on the brown wire.

Battery voltage on the white with black trace wire.

Grey with red trace is an earth.

Those are between the sensor and the DFI module; DFI terminals J, N, and M respectively.

If you have a digital tachometer, you should get an rpm reading with it connected between the N terminal - W/B - and the M terminal or an earth. The "rpm" will be engine rpm, ~ 850 at idle, divided by 2 (= camshaft revs), divided by 3 (four stroke, 6 cylinder) if the tacho is set on "6-cyl.").

Alternatively, the sensor should switch a test light across N and M on and off as the engine is rotated by hand.

Also, the DFI module switches a 5V signal between terminal F on the DFI and D3 at the PCM.

[ragrim]

just an update on this, i took the cam sensor from my old engine and put it in and reset my computer, hasnt made a differance, still getting the no camshaft position sensor error.

i didnt have a torch handy to look in the hole for the magnet on the cam. If the magnet on the cam has come off, how much work am i looking at to fix it?

Id like to test the wiring from the sensor to the DFI and ECU where the wires go but i only have a wiring diagram for a VS, i assume they would be slightly differant. The wiring on the sensor itself looks intact but the wires are very stiff and i would say there is a small possibility they could have a broken connection somewhere, just dunno where the wires go.

This weekend im giving my car some much needed TLC, new shockies and stuff so ill get under the bonnet and see if i can see the magnet in the hole and ill also try the test light thing to see if i can get anything from the sensor.

[VrWagz1]

The likely hood that you have a broken wire is very low, but possibly a corroded connector is possible. But i wouldnt bother wasting your time tracing the wires until you do the above readings that cheap6 has put up for you. Possibly first look for that magnet.
At a guess if its just got a little hole that the magnet sits in(like above posts suggest), then it would just be a matter of taking the inlet manifold off(and associated bits) to get into the valley and drop a new magnet in with a better glue this time Hopefully the biggest cost will be a couple new gaskets.

[wortus]

I'd be unplugging the sensor and testing it's output as suggested by Cheap6. Alternatively if you have a CRO you can look at the output signal. When you changed the IAC did you clean out the throttle body?
Also since this problem started has your fuel consumption gone up? the engine reverting to burts fire mode on the fuel injectors will probably increase fuel consumption.

[Cheap6]

So what engine is it - VR or VS?

They are very similar in the way the the ignition systems and DFI work anyway so with the possible exception of a few wire colours being different, the VS wiring diagram should help. D3 at the PCM is for VS, VT and VX. VR is ??

The terminal designations are cast into the plastic terminal connectors on the wiring harness for both the DFI and PCM.

There is a step by step with pictures on the web describing how to replace the magnet through the hole for the sensor by epoxying it into place (= search). The depth of the magnet in the sprocket is important. That is much easier than:

The "right" way to do it is to remove the timing cover and cam sprocket and push the plastic carrier and magnet into the sprocket from the back.

[ragrim]

When i changed the IAC i used some carby cleaner and cleaned out the thottle body realy well. My fuel consumption seems to a bit worse than my old VS but i have not done any full tank testing so im not 100% sure.