Safety Shutdown for Low Oil Pressure?

1997 Dodge Grand Caravan 3.8 liter V-6 engine. While wife was driving
it, became very sluggish, unresponsive. She thought she had a flat tire
so pulled off the road. As she was pulling off the road the oil light
came on. After verifying no flat tire, she started the vehicle and it
ran normally. We will check for low oil level.

Q. Does this engine have a safety shutdown if oil pressure gets too
low? If so, is that what likely occurred?

 

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 -
5 below; today it is +35 degrees.

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')

 

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.

--

(Jim, single dad to Lesleigh [Autistic] 04/20/94)

"What, Me Worry?" A. E. Newman

Please note: All unsolicited e-mail sent to me may, at
my discretion, be posted in this newsgroup verbatim.

 

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:

12 Battery or computer recently disconnected

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

54 No sync pickup signal during engine rotation (turbo only)
OR
54 Internal logic module fault ('84 turbo only) - or camshaft
sensor/distributor timing (7)

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