CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Toyota low oil engine shut off

My 97 Rav4 shut down on the highway yesterday. Checked the oil when I lifted the hood. It has only been 4500 since the last oil change, but the oil was barely registering on the stick. The engine will turn over, but will not start. Do Toyotas have an auto shut off mechanism when the oil gets too low or is my Rav4 toast? There were no warnings, temperature, low oil light, nothing.

I don’t believe there is a low oil shut-off. I’ve never seen one on a Toyota. If the engine still turns over, the problem could be the timing belt or the fuel pump. Oil starvation usually leads to engine lock-up, unless something else broke. When did you replace the timing belt? It should have been replaced every 60K miles or 7 years.It should be on it’s 3rd timing belt right now.

No, I don’t believe there is a low oil shut off. An easy way to find out is to add a couple of quarts of oil to bring the oil level up to normal. At that point the motor would run since the low oil condition was corrected. Most likely you have another problem. A broken timing belt is a pretty good guess.

You likely have another issue. But why oh why don’t you ever check your oil??

I usually check my oil but there, have been no signs of using oil. Thank you to those who offered helpful information. Sometimes people get so busy with other things that they don’t think to do basic auto care. Same reason they don’t update virus software, pay bills on time, let the dog out to pee. The point is that we all overlook things and sometimes have deal with the consequences. However, I think that I understand that I should have checked the oil more often now that this has happened.

No. No car has a low-oil shut off mechanism. If they did the roads would be littered with non-running cars!

Timing belt failure, ignition system problem, many things can make a car not run.

1 Like

@asemaster

Some GM vehicles have an oil pressure switch that cuts power to the fuel pump if the oil presure drops below 4 PSI.

Tester

Your vehicle is 16 years old…How many miles on it? Yeah, it sounds like a timing belt or fuel pump failure…

1 Like

@Tester, well, kind of but you’ve got it backwards. The oil pressure switch is there as a fail safe to make your car runs if you have a failed fuel pump relay, not to shut the engine off if there’s low oil pressure. Your article states that. Once the engine is running you can lose all oil pressure and the fuel pump will continue to run. Conversely, if your fuel pump relay is bad, you will have a long crank time but the fuel pump will run once the engine cranks long enough to generate oil pressure.

No car does or should have a low oil shut off. It would be absurdly dangerous.

1 Like

@asemaster

The oil pressure switch to the fuel pump is a safety feature. If the vehicle is in an accident that causes the engine to shut off or if the vehicle lands on it’s side/top there’s no oil pressure, so the switch opens turning the fuel pump off.

Ford uses an inertia switch for this safety feature.

Tester

1 Like

Uhh, no. Look at the wiring diagram you linked. The oil pressure switch and the fuel pump relay are two entirely separate systems designed to power up the fuel pump. As you can see, opening up the oil pump circuit while the fuel pump relay is closed will have no effect on fuel pump operation, and neither will removing the fuel pump relay while the oil switch is closed.

If the vehicle loses oil pressure, whether it’s upside down or not, the pump stays running.

If the car is in an accident and the engine stalls, the fuel pump will not run because the pcm opens the relay because it doesn’t see crankshaft revolutions.

1 Like

http://answers.yahoo.com/question/index?qid=20070924184656AATPpms

Tester

1 Like

Ehh, wrong again. The only way low oil pressure will cause the pump to not run is if the fuel pump relay is faulty,removed, or not closed by the pcm. The wiring diagram clearly supports this. It’s a simple system.

1 Like

@Tester I have to agree with @asemaster on this

We have plenty of GM vehicles in our fleet. We have the service manuals (including the wiring diagrams) and I’ve worked on the oil pressure and fuel systems enough times.

The oil pressure switch is not part of any “safety” system to shut off the fuel pump.

1 Like

There’s two problems here.
First, the one causing the no-start.
The other is driving 4500 miles without checking the oil; being 16+ years old makes it worse.
You say “only 4500 miles” like it goes much further between oil changes.
If you’re going more than 5000 miles between changes with a mix of city/highway driving then it’s no surprise that it’s burning oil now.

When the utilities get cut off, the computer gets a virus attack and there’s pee on the kitchen floor there will be no one to blame but yourself.

I had a 1998 Oldsmobile intrigue that had an oil level monitor and would shut down the engine if it decided it had no oil. And yes it was a very dangerous feature. I was driving rather energetically on a curving expressly ramp and plastered all the oil against the right side of the pan and it shut off the engine in the middle of the curve. Fortunately my arms were still used to driving tractor- trailers w/o power steering.

the engine on any car with variable camshaft timing will shutdown when the oil pressure is low because the it affects the timing. just fixed a 2014 camry that stalled only when braking hard, because it was 2.5 qt. low. old Honda VTEC engine would hardly run when low on oil.

Huh? No. At least in the old VTEC cars, low oil pressure just meant you’d never switch to the high cam profile. It wouldn’t shut the car down.

@ Nianzhong
Can you please post how did you resolve the issue. what was the issue. I am in similar situation wit my 2008 Rav4. I will appreciate your response.

Thank you.

Well from 2013, I think the answer was fairly obvious. Don’t go 4000 miles without checking the oil and keep the oil level up to the mark on the dip stick. That should solve the problem, but hey that was a 97 model. Maybe they give you a buzzer or a light now.

3 Likes