While driving on the freeway, near the end of a 90 minute trip, the van (2008 Toyota Sienna) loses power. Tach remains around 2k but no power gets to the wheels and I am, in effect, coasting. Power steering drops out. Then the engine stalls. No check engine light then or now but the light is working.
After a few tries, the engine restarts. I make for home, the same thing happens again. Again, I get it restarted and I am able to make it home.
That was last night and the van is currently parked.
When you press on the gas pedal during there is no forward motion does the engine rev up or does it remain at 2000 RPM? If it revs you may have a transmission problem. I’d check the fluid first since low fluid or degraded fluid is a cheap fix if it works.
No, there was no RPM spike when pressing the gas pedal. I did check the transmission fluid just now, the level look good and the fluid is not “dirty” or gritty.
I agree with Tester on the crank sensor, they can get hot and crack open and stop working but when they cool down the work again, but normally not for much longer…
You can take a chance and replace it or get a scanner that can read if you are getting a crank signal when not running…
Now does it just stop running, or does it slowly loose power like it is bogging down?
Now does it just stop running, or does it slowly loose power like it is bogging down?
Both times it happened things moved fairly quickly, first power was lost (tack stayed around 2k with no spike for more gas). Within a few seconds (more than three but less than ten) the power steering would go out and the engine would stall. So it seems fast to me but it wasn’t like “finger snap” fast.
Yeah, doing it correctly showed it is low and dirtier than it looked on first glance. I don’t know if that is because having it on stirred up stuff or what. It’s bad enough that I feel it should be flushed rather than just adding more. I have never done a flush/drain.
If that fluid has not been changed then just top it off, you will never hurt it topping it off but you can KILL it changing or flushing it when it has not been properly maintained or burnt… I would advise to take it to a dealer or transmission shop to be evaluated and safe to flush and or change…
It would be very unusual for the transmission to cause an engine to stall.
The tachometer signal is based on the crankshaft position sensor signal, seems that the CKP sensor is working. When the engine loses power, it continues to rotate due to the wheels/transmission rotating.
You need to analyze the system while driving using a diagnostic scan tool and fuel pressure gauge.
While adding transmission is needed, I’m not sure that’s the source of my experience last night. The crankshaft sensor, is there a way to check that? I don’t have a check engine light so I don’t think a code reader would show anything but I may be wrong there.
A failing or failed crankshaft position sensor may cause the check engine light on your dashboard to come on. A diagnostic scan tool will show a code between P0335 and P0338**. The check engine light doesn’t always come on, though, so you could be experiencing any of the above symptoms for some time before you see the warning light.**
Many possible culprits, good ideas above. I think if I had that problem first test I’d do is make sure the electrical system supply voltage is good (12.5 - 14.5 volts) when symptom first occurs.