2008 Saturn Vue XE low oil pressure warning

nickb2

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#16
Ok Bill, will try a other way, but it will black on white. Jim would be better here but he has other things on his mind.

Screenshot (599).png
 

nickb2

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#17
So I still see grey for 5 volt reference. If 5v there, and ground is good, it must be a PCM issue.

Bypass like I said. But Kev2 seems to have another idea, and I would like to hear/read it.

He is a good old man.!!
 
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#20
Were the spark wires ever replaced in this vehicle? Really had seen some messes by installing aftermarket sets where these wires are way too long hanging all over the place.

Wasn't a problem when the oil pressure switch directly ignited a light bulb, but sure is when using a high impedance ECU input, EMI could be the cause of that lamp coming on.

EMI is electromagnetic interference. Original wiring location must be maintained. Other problems are using the ECU ground for other things as well as adding aftermarket stuff, to this 5V isolated ground for these computer circuits. ECU is grounded, but at only one point, such as thing as ground loops. Not only could that oil sensor lead after the intermittent ground, but also the ECU ground wire.

Only takes a small fraction of a microampere to trigger these things. And doesn't have to be true ground, moisture can cause these problems. In particular salt water that is more highly conductive.

Yeah, rain does have something to do with it the way they are designing electronics today. Even adding a 1,000,000 ohm resistor across these inputs can help prevent this, but that adds costs, have to think about the stockholders.
 

billr

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#21
The resolution on that last schematic posted is better, but now it is "cropped" so I can't see the whole page. How are you determining this is on the 5V circuit? Does that GRY wire go off to a labeled 5V source on another page?

Edit: Doc, did you ever "tee" the sensor and your remote gauge, to see what the pressure is doing when the light is flickering?
 

infj23

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#22
Hello Gents,
Me again. Still wrestling with this dinging car. I have checked it every way I know how, which is apparently not enough ways.
Today I had the brilliant idea of finding the chime and disconnecting it. Turns out the chime is the radio--so not a good idea (my daughter's car).
Here is the latest news: my daughter has figured out she can make the thing chime by using the windshield washer fluid. When she washes her windshield, it is almost guaranteed that the oil pressure chime will sound. I hope that helps isolate the problem and you can tell me where to look for a loose connection or some such thing.
Either way, how do I bypass this? Several post have suggested bypassing it, but I'm not sure how to do that. Any specific instructions to do that?
Thanks so much. This thread is pretty old and my daughter is ready to trade in the car, which would not be a good financial decision.
Thank again for all of the help and ideas!
Doc
 

billr

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#23
Did you ever "tee" in your gauge to confirm the oil pressure is fine while the blinking/dinging is going on? I'm kind of just asking, I think it is very likely this is an electrical problem. Unfortunately, I still need full and readable schematics to continue much more.

Edit: Obviously, I am further confused because the schematic posted shows two wires to the sensor, but the sensor itself is 3-wire. Doc, please confirm that it is 3-wire.
 
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nickb2

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#24
I am seeing "C" as the chime/signal which grounds out in ECM and proceeds to cluster via BUS line, "a" = ecm 5+, and "b" = ecm -/neg rail.

It is a three wire. I already posted all this.

Screenshot (682).png
 
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nickb2

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#27
Have we asked if the oil pressure light does it's bulb check at startup?

I just want to know if this dinging engine has good oil pressure, then want to know if you have tested or replaced the sensor. If yes to all that and is good, still a chime noise. Pay the five bucks to get that bulletin. I sure won't. I can't find it. Scour the saturn forums, maybe they have that #pip4473. Chimes in exactly like your problem. Pun intended.:cool:

So again, if all above check were done, we are looking at a ECM/bus line issue or a cluster issue. That's it, that's all.
 
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nickb2

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#28
Of note, since a low oil pressure message to IPC is or should be a high priority message, the radio will receive this via the IPC and the frequency of the chime should be at a fast rate, about 200 pulses per minute.

When you hear this chime occur, is it fast paced as I described? It's like if you left your lights on, ignition off and door open. The chiming should be high rate. The BCM is sending a high priority message to you via the radio telling you the battery will die!!:eek:

Same if your rolling and oil pressure drops, should get same high priority message via radio and also IPC indicator on. Engine failure coming to your local theater soon!! :eek:

The DIC (driver information center) should also read this message. "Low oil pressure Stop engine"
 
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nickb2

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#29
If the oil icon lights up at bulb check then goes out, and DIC message do not appear and no low oil indicator on when engine running, and physical oil pressure is good then the oil pressure system is functioning both mechanically and electrically in a proper fashion.

I am a bit mixed up, this is very old thread from 2015, then from march 2016, and now past mid april 2016. So plz verify that when the chiming occurs, do not turn off engine and verify what the DIC is saying.

All audible chimes pass through radio. Any aftermarket crap installed that we should know of, that may be routed through radio wiring? Maybe someone tapped into a serial data line(BUS line). Who knows?

Cuz really, if you look at it my way. If all is working, and no IPC/DIC indications, bulb test at initial start up illuminates all the bulbs and oil pressure reading is and has been verified as good in mechanical nature, there might be something else totally unrelated to oil pressure here going on.

This must not be ruled out as a possibility. You say this is your daughters car. So you are not the daily driver. Has it done the problem to you? Or are you going by what your daughter is experiencing? I am not saying your daughter is illiterate or anything. I am just saying, try to get it to reproduce the problem with a physical gauge hooked up in "T" fashion when you are at the wheel.

If chiming occurs and you can see the actual oil pressure, leave engine running and quickly unplug the oil pressure sensor. What happens? What does the DIC say? Do any P codes or check engine light come on? Does the engine shut down(I highly doubt it, but some GM's have this option)?

Car will be fine engine running as long as that oil pressure gauge is giving you 33-35 as you say you had back when!

@around 2000rpm 30-45psi is normal operational pressure for this engine.

If any after market stuff is hooked up to radio, or a Walmart thing is in there instead of the oem, these things need to be checked for proper installation.

Circuit 5060 of radio is dark green and is your low speed GMLAN serial data. Do you have the X1 radio receiver. Do you know which radio option this car has?

Is it the navigational one U3U, or the U2K? There are 4 or five different radio packages for this series.

I do not want to pull you into the weeds, same as you would not want to with us. But from what your saying, start pulling some B codes, U codes, investigate any wiring that looks suspicious in between the instrument cluster and radio. Especially if there are any after market things installed. Alot of ppl tap into anything that has a ground and 12 volts without consideration that they might be interfering with LAN/BUS line communications from module to module.
 
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#30
Hi— I was wondering what the fix was for this? I just bought a used 2008 Vue 2 days ago and went to use the windshield washer and the low oil pressure light comes on, Onstar says my oil pressure is fine....