Engine turning on and off rapidly when stopped

Bonzocat · 12-17-2005, 09:01 PM

I've had a little oddity that I haven't seen on the forums... When my '05 is stopped on a hill, heading downhill only, the engine kicks on and off in rapid succession. If I put my foot down on the brake a little harder it seems to stop. Has anyone else had this happen? Any thoughts?

One more thing that has bothered me...if I'm accelerating fairly rapidly while turning from a side street to a main street, the transmission seems to skip a beat...its like it completely loses power for a fraction of a second and then pops back in causing the car to jolt. Seems like that shouldn't be happening.

Any input would be appreciated!

**efusco** · 12-17-2005, 09:15 PM

Here's a recent thread on this common question:
http://priuschat.com/index.php?showtopic=13403

prius04 · 12-17-2005, 09:24 PM

I've got nearly 22K on my 2004 Prius. My Prius has done this about once per month since the beginning. I stopped worrying about it at about 2K, that's not to say something isn't wrong tho. It's like the car can't be sure whether to shut off, or stay on. My daughter's Prius does this as well. I think she would say it happens more than once per month.

As for the transmission hesitation, this sounds like the traction control has kicked in. Whenever the engine detects that one of the wheels might spin freely, the computer puts a stop on the whole thing. So there is no "laying rubber" with the Prius.

On the other hand, ALL cars hesitate when you push on the gas. Since our car has a computer that has to make sense of what you want, using what you did to the gas pedal as a source of data, the computation also takes a split second.

If I've got it wrong, others will come along as well.

**efusco** · 12-17-2005, 09:43 PM

Quote:

Originally posted by Bonzocat@Dec 17 2005, 08:01 PM
One more thing that has bothered me...if I'm accelerating fairly rapidly while turning from a side street to a main street, the transmission seems to skip a beat...its like it completely loses power for a fraction of a second and then pops back in causing the car to jolt. Seems like that shouldn't be happening.

Any input would be appreciated!

[snapback]175033[/snapback]

Sorry, didn't even notice that part of your question. That's the TRAC (traction control) kicking in. It'll do that as described by the answer above.

DanMan32 · 12-18-2005, 02:03 AM

Was the battery SOC at 8 bars? If so, the computers were probably trying to bleed down the SOC a bit.

Bonzocat · 12-18-2005, 09:20 PM

Thanks, guys! The link Evan posted was very helpful. Eased my mind.

And, Dan, I actually didn't look at the SOC bars, but I'm assuming that the energy bleed was the intention. I'm in LA, so freezing temperatures are not the answer.

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12-17-2005, 09:01 PM	#1
Bonzocat Join Date: Nov 2005 Posts: 5 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I've had a little oddity that I haven't seen on the forums... When my '05 is stopped on a hill, heading downhill only, the engine kicks on and off in rapid succession. If I put my foot down on the brake a little harder it seems to stop. Has anyone else had this happen? Any thoughts? One more thing that has bothered me...if I'm accelerating fairly rapidly while turning from a side street to a main street, the transmission seems to skip a beat...its like it completely loses power for a fraction of a second and then pops back in causing the car to jolt. Seems like that shouldn't be happening. Any input would be appreciated!

12-17-2005, 09:15 PM	#2
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 14,042 My Car: 2004 Prius Package: #9 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 23	Here's a recent thread on this common question: http://priuschat.com/index.php?showtopic=13403

12-17-2005, 09:24 PM	#3
prius04 Join Date: Aug 2004 Location: NorthEast USA Posts: 1,155 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I've got nearly 22K on my 2004 Prius. My Prius has done this about once per month since the beginning. I stopped worrying about it at about 2K, that's not to say something isn't wrong tho. It's like the car can't be sure whether to shut off, or stay on. My daughter's Prius does this as well. I think she would say it happens more than once per month. As for the transmission hesitation, this sounds like the traction control has kicked in. Whenever the engine detects that one of the wheels might spin freely, the computer puts a stop on the whole thing. So there is no "laying rubber" with the Prius. On the other hand, ALL cars hesitate when you push on the gas. Since our car has a computer that has to make sense of what you want, using what you did to the gas pedal as a source of data, the computation also takes a split second. If I've got it wrong, others will come along as well.

12-18-2005, 02:03 AM	#5
DanMan32 Join Date: Aug 2004 Location: Tampa Bay, FL Posts: 3,775 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Was the battery SOC at 8 bars? If so, the computers were probably trying to bleed down the SOC a bit.

12-18-2005, 09:20 PM	#6
Bonzocat Join Date: Nov 2005 Posts: 5 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Thanks, guys! The link Evan posted was very helpful. Eased my mind. And, Dan, I actually didn't look at the SOC bars, but I'm assuming that the energy bleed was the intention. I'm in LA, so freezing temperatures are not the answer.