Safety Shutdown for Low Oil Pressure?

I've never heard of that. The oil light probably came on because the engine either stalled or was so close to stalling that it wasn't maintaining oil pressure.

-- Christian

I agree with Christian on this. It was most likely a stall. I was having intermittent stumbles and stalls at highway speeds with my 1993 Voyager, due to a bad O2 sensor.

I would suggest getting it scanned to see if there are any stored codes.

-KM

It's only a 1/2 quart low on oil. I suspect it might be water in the gas. We're in Minnesota and she filled up a few days ago when it was -

Still, that's good advice to check the codes. There must be something stored because the "check engine" light came a while ago, I did the turn the key in the ignition to read the codes trick and it returned back a 12 indicating the battery had been disconnected. (It had, I took the cables off and cleaned the connectors and battery terminals in anticipation of winter about 6 weeks ago). I figured disconnecting the battery and reconnecting it would clear the codes, so I unhooked the battery for about 5 minutes but the "check engine" light came on again shortly afterward. I did the ignition switch trick again and got another code 12--battery was recently disconnected. Well, duh, I had just done that. I thought it was a catch-22: disconnect the battery to clear the codes, but doing so gives a code that the battery has been disconnected. I've been meaning to take it to my mechanic and have him clear the check and/or clear the codes. Looks like a chore for Monday.

Was 12 really the only code? You should have at least seen a 55 (end of codes, i.e. th-th-that's all folks) as the last code reported.

Ordinarily, if there are any codes stored, you'll see a 12 (I've seen the claim from people I respect that this is a standard; I've never seen it in a manual, but I've also always seen a 12 come first), any real codes, and a 55.

My understanding is that just 12-55 means "battery recently disconnected".

Hi...

Probably preaching to the audience, but you do know that you'll still get the "real" trouble codes after the 12 ?

Just keep watching until you get to 55. If there are any between the 12 and 55 those are the ones that interest you.

Take care.

Ken

If it got sluggish BEFORE the oil light came on, then the oil light was a symptom (stalled engine, too-low RPM) and not likely a cause

If the oil light was on long before she noticed it, then the engine might have been in the process of seizing. However, it would not "run normally" after that.

No. I can't think of any vehicle that shuts down when the oil pressure is too low, and its a bad idea anyway because that would take control away from the driver and possibly cause accidents. Stationary engines (compressors, generators, etc.) do have oil pressure safety shutdowns, but it is inapproprate for a car to shut down at ANY time that is not under driver control. That is why its so important to OBSERVE when the oil pressure warning light comes on. The DRIVER is the safety shutdown!

Coincidentally I am helping a guy troubleshoot his GMC diesel service truck for an an intermittent engine shutdown problem - it in fact has the oil pressure switch circuit tied into the injector shutdown system. He's frantic to get it fixed because he says it is very dangerous as he looses brakes and steering when it happens. We haven't narrowed it down to the switch yet as there are several fuel system shutdown interlocks that also could be the culprit.

Hmm - perhaps I ought to suggest to him that we bypass that switch shutdown permanently - with the understanding that he risks loosing his engine if he looses oil pressure - perhaps a valid trade off. He only occassionally goes on the highway so has been lucky that the shutdown has not occured at speed - but he also is frightened of using it on the highway, which is not good for business. A plus would be if we bypass the switch and the random shutdowns stop.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

On Fri, 08 Dec 2006 17:17:44 -0600, Steve spake thusly:

My 1984 VW Rabbit had a low oil pressure shut-down. It didn't shut down right away. There was a red light and a buzzer for 10 seconds [I think] before it shut off. You could then restart it for 10 seconds then it would shut off again. I never had this happen to me but it was explained in the owners manual.

Eureka! I just rechecked it now being sure to wait until I saw the 55 code. I got 12-54-21-55. According to Allpar.com these mean:

21 Oxygen sensor signal doesn't change (stays at 4.3-4.5V). Probably bad oxygen sensor

55 End of codes

I don't think a bad O2 sensor would cause the vehicle to stall out. What are your opinions on the code 54?

I'm still leaning to water in the gas, but my ears are wide open to other, more learned opinions.

Hi...

Glad you got it; that message was a long time ago :)

Looked up 54 in my book for you, it's a little clearer, I think.

"No camshaft signal detected during engine cranking"

I don't have a more learned opinion, I'm just an old retired electrical guy who loves cars, so wait until the mechanics here confirm, but I'll betcha a dollar against a stale donut that they're going to suggest you change the cam sensor.

Take care.

Ken