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Oil LEVEL Light... Female NON-mechanic working on my own car!

Buick Riviera 1998 Supercharger

I am a female non-mechanic trying to fix this car myself.

Oil LEVEL light comes on and car shuts off. Take note…NOT oil pressure light- which is the one that looks like a genie lamp. It says OIL LEVEL. This trips up every mechanic I have spoken to.

Doesn’t stall (like sputter and die) just shuts off like a safety switch has been tripped or something. But it is an older car 1998 Buick Riviera Supercharger. You wouldn’t think it would have that safety feature but maybe. You can start car but if I put it in reverse or even when I am driving the car oil LEVEL light will come on and car will shut off. Only happens when we get to normal operating temp.

So here is what I did. First, changed oil and filter just to be sure there was no odd clog and it was due anyway. Still had the same symptoms.

Next, I discovered that we have a separate supercharger oil reservoir. No mechanic that I spoke to knew this. I changed the oil in the reservoir because the level was low and I am sure that it has never been changed. Didn’t work.

Next, I changed the oil PRESSURE sensor because even though I know it says oil level I figure it has to do with a misread on pressure. Didn’t work.

Next I disconnected the wires going to the oil level sensor to test and see if it is a funky level sensor. Plus I didn’t feel like changing the oil again in order to change the sensor. Didn’t work.

Next. I changed the oil level sensor. Still…a no go. Drive for a bit and get up to normal operating temp and oil LEVEL light comes on and car shuts off.

Note: there is no sound. No sputtering or clanking or anything. (Other than the words coming out of my mouth.)

I am stumped! I want to work on this myself so if someone could help me out and give me detailed instructions I would be grateful.

Between the level sensor and the light on the dash there is wiring, connectors and some circuitry to read the signal from the sensor and decide to turn on the light.
There could be a problem with any of these.
The circuitry may be in the dash cluster or in the engine computer.
Talk to someone at the dealer parts counter and see if you can get access to the factory service manual.
It will have a wiring diagram to show what’s what.
With luck and charm you might be able to avoid having to buy this expensive manual and find someone who can figure out how to disable this feature if it can’t be fixed.

The oil level sensor sends it’s signal the computer. The computer then turns on the oil level light on the dash. If the computer detects that the oil level gets too low it’ll shut the engine off.

Check the wiring at the oil level sensor. Black goes to ground and brown is the signal into the computer.

Tester

I did try and clip the wires between the oil level sensor and wherever those wires go. That did nothing so I ended up reconnecting the wires. I was wondering if they were maybe too corroded and needed replacement.

You’re going to need a repair manual for this one, because you’ll need to measure the oil level sensor output.

I suspect that the ECU is shutting the fuel pump off to protect the supercharger because it isn’t getting a proper signal from the oil level sensor. But I unfortunately don;t have access to schematics or on vehicle test protocols for your car. If you can’t get a repair manual, try requesting of the local GM dealer’s parts department a copy of GM’s test protocol for the oi level sensor, and perhaps a copy of its schematics.

Sorry I can’t be more help, but perhaps this will set you on the right track.

Try installing a jumper wire at the connector for the oil level sensor. The sensor is a normally closed switch. If the oil level light goes out there’s a problem with that new oil level sensor you installed. If the light stays on then there’s a problem with the wire that goes to the computer, or a problem with the computer itself.

Tester

Tester…how would I install a jumper wire?? Could I just disconnect the brown wire going to the computer? Sorry for dumb questions.

Unplug the connector to the oil level sensor. On the connector install a jumper wire between the two pins/slots that would plug onto the oil level sensor.

Tester

Well I am going to go crawl under my car and put in a jumper. Now here is the kicker…the oil level light does not come on until I am at normal operating temp. So if ,say, this light does not come back on and my car does not shut off, is it the harness (wires) that needs to be changed or do I have to replace the oil level sensor again.
Because When I did clip the wires to the sensor last time I hooked them together to form a loop on the engine side of the car (not the side near the oil pan). The light still came on. So would that mean it is the harness (wires) that is bad??

Or would I still need to try the jumper wire to find this answer out?

And is there a way to disconnect the shut off safety feature?

Looking at the schematic, that oil level indicator seems to be attached to just a switch (marked Barney dinosaur purple) that’s normally closed.
That presumably means, when all things are normal and the level is okay, pin 58 (marked red) of the PCM is grounded. You could just short the switch and see if it goes away but it would still leave the wire to the PCM to maybe open up intermittently. In other words, if the wire has a problem, shorting the switch or replacing it will not make the problem go away. If you look at that ground lug on the one side of the switch, if that has a bad connection, the switch will appear opened to the PCM. I’d check that lug as well.

If that still doesn’t help, If you tied a wire from pin 58 to ground, it would take that switch and the wiring to that switch totally out of the system. Maybe strip that brown wire close to the PCM and solder a wire from it to ground.
Or maybe take the connector to the PCM off and clean it really well with some contact cleaner. Look if that brown wire is crimped properly, etc.

If the condition still happens, it will then be for some other reason – probably the PCM.

Whoa. Speak to me like I am five. I am a non-mechanic. What is a pcm??

That’s the power train computer. Basically the thing that turns the light on and decides whether your car should run or not.

Listen, this is not for the faint of heart. If you’re not up for this, just pass it on to your mechanic and see what he can do with it. I suspect your problem is electrical in nature.

I am not faint of heart. If I were I wouldn’t be doing any of this. :wink:

But ok so I am first going to check to see if the crimp on the wires is ok. But let’s say it is. Should I maybe just try and replace the wires (harness)?? That part is only 15 bucks.
Or could I test it like Tester suggested? By putting a jumper in?? Or did I essentially do that already when I clipped the wires and connected them together??

If you cut the wires and connected them together it’s the same as installing a jumper wire.

Tester

Ok so if the light still persisted the next step would be the wires themselves? Correct??

Well I’ve got a 95 factory manual not a 98. I’m not competent enough to read the schematic much and doesn’t look like any tie in to the fuel pump that is possible I imagine for 98. There is an “oil level module” though under the IP on the right hand side attached to the HVAC somewhere. The diagnostic chart says either wiring connection, short to ground, replace the sensor which you already did, or replace the module. Again nothing about shutting the engine off but if it feeds back to the computer with the oil pressure switch that would shut the engine off. Not much help but could be the module itself.

Ok so should I check the wiring and the Oil level module in the Instrument Panel?

It says I do not have an oil level module on a 98 ?? I checked with AutoZone?? Is that correct?