Won't go over 22 MPH and acceleration problems

Don't say his name. If you say it three times he appears.



Tom

 

I think the PC member "who shall not be named" is now hanging out of the Leaf boards and we're safe for now.

 

No DTCs on the paperwork?

 

Darn it, that's twice. No one say his name a third time.

Tom

 

Sounds like the OP's problem was traction control kicking in due to the low tire and/or temp spare. I didn't see anything in the dealer report that they actually fixed. Clearing the codes may have been all that was necessary.

 

*clicks heels together* EVPV!!!!!!!!!!!!!!

 

Thanks for following up. It does sound as though the nearly flat tire was the cause; a good reminder for everyone to go check their spares, before they are needed.

 

Since you may want toreplace that junk jack, I would suggest a elec 12V that works off the accessory plug. ( Bought at Harbor freight ) It works great, but I still carry a mechanical jack from a Civic I once had, as a precaution. After the original tire was reinstalled, a reboot "may" have removed all warning lights. :cheer2:

 

Do you have more info on this 12V jack? I don't think I've ever seen one when I've been in HFT before. I did just buy a nice, low profile racing jack from them a few months ago for swapping my winter and summer tires on and off the car. My small little floor jack just wasn't getting it high enough and was a lot less sturdy.

 

Just ask, you may have to order if they have run out.

 

Ah yes! patsparks has the right idea. I had this happen to me and I could not go over 25 MPH with out the car cutting power. I had a flat on the back tire a few ears before and did not have the same problem. Lesson learned...THANK YOU patsparks and Pruis chat!!!

 

I think what happened here is that first spare tire made traction control system to limit top speed to 22MPH and then driver pushed and/or stomped gas pedal harder than normal and that broke it (it probably was already marginal).

 

It's a long, complicated story, but I have a bit of a theory:

The "slippery conditions" light is actually a traction control light, and it comes on when it detects the front drive running faster than the rear wheels. This it interprets as slippery conditions, so it limits the power to the drive wheels. This may account for the limited speed you experienced.

Accounting for the slippage is a bit harder. There are no clutches, but there is a torque-limiter, which is designed to slip under heavy strain. Perhaps it's been damaged, and it's slipping. That may account for the sound of the engine "groaning to a stop" and over-speeding.

As for the flat tires, I don't see a connection to the other problems; not that there isn't one.

 

Makes sense. But, is it documented anywhere in the car manual?

 

-------------------
Something similar happened to us. But thankfully the problem seemed to resolve after the tire was replaced. Here are details so far:
2008 Prius, 65,098 miles
Michelin tires installed on 7/11/2014 (Costco) at 54,000 miles inflated with nitrogen. New service packs (G) were installed.

My husband is currently using this vehicle. Last week (5/2015), the tire sensor reported low pressure. Visually, the front driver's side tire didn't appear super low but was at about 22 lbs. My husband filled the tire with a bicycle pump to the correct pressure and drove to work (about 25 miles). After work, the sensor reported low again. He drove to a gas station and they filled it again to the correct pressure and he drove home (about 25 miles). He assumed he had a slow leak and intended to get it fixed the following Monday.

We left for the weekend (in the other Prius). Upon our return, the tire was visually flat. So this was 2 days later. Without moving the car, he jacked it up and replaced the tire with the spare. There was nothing in the visual inspection of the flat tire to explain the loss of nitrogen. Also, he doesn't remember hitting any major pot holes or anything that would damage the tire. The tire was changed without incident or injury to the car.

The next day, I drove the car to Costco (5.5 miles) for warranty work on the tire. The car pulled out of the garage fine. I noted that the low tire pressure light was on. My assumption was that the flat tire in the back was still be signaling the car about the problem. I pulled out on the side street and the slip indicator [picture of a car with wavy lines] came on. It was sunny and the streets were dry. I pulled over and visually inspected the spare tire. It looked fine with plenty of pressure. I got back in the car and the slip indicator was off so I continued. I was in heavy traffic. About 5 minutes later, I noticed that the slip indicator came on again. I saw my speed was about 22 mph. It was then that I realized that the slip indicator was turning on once I reached about 22 mph. I was able to stay below that until I reached a hill. I needed to accelerate and I noticed that the accelerator wasn't responding when the slip indicator was blinking. I sweated out the rest of the drive to Costco with cars tailing me despite my hazard lights blinking.

While I was waiting in Costco, I Googled my problem and found Jaay Dee's posts here.

Costco analyzed the tire and found no problems. Finally, the technician replaced the service pack (valve) because "it looked funny". Sigh.

Only when I asked about the condition of the spare tire did he indicate it was low at 20 lb. He had filled to 60 lb. it but wasn't going to mention to me. He said there was no damage to the tire rim.

I Googled the nearest Toyota location (if I needed it) and then sweated out the return home. The only problem I noticed was that the Maint Required light flashed 5 or 6 times and then went off. My husband doesn't remember this condition prior to the tire pressure problem. According to the manual, this indicates the "Engine Oil is scheduled to be changed" (page 430, Publication No. OM47613U). Acceleration and braking were fine. No other indicator lights illuminated.

According to the manual, page 446, when the spare is on, "the vehicle speed may not be correctly detected, and the following systems may not work correctly,

• ABS & Brake Assist
• Enhanced VSC
• Navigation system"

On page 170, the manual defines Enhanced VSC as "Vehicle Stability Control" where it [h]elps the driver to control skidding when swerving suddenly or turning on slippery road surfaces." There is a picture of the slip indicator light [car with wavy lines] and the message that reads: "If the vehicle is in danger of slipping or the front wheels spin, the indicator flashes to indicate that the Enhanced VSC have been engaged. A buzzer (intermittent) sounds to indicate the enhanced VSC is operating." Note: I didn't hear a buzzer.

I am now safely at home waiting for the tire to deflate again and then back to Costco for more fun. I will update this post in the next week.

Other notes:
I have seen posts (Patspark) in this thread and on another thread that suggest one should not drive the car with the spare on the front. According to some users, if you have a flat on the front you should remove the flat AND a tire from the back and move it forward to the front. Then put the spare on the back tire. We had never heard of this. PLEASE NOTE: in the 2008 Prius manual, section "5-2 Steps to take in emergency, If you have a flat tire" (pages 438-447, Publication No. OM47613U), there is no mention of this. Also, the employee at Costco that repaired my tire was not aware that this was a problem in the Prius or any other car) Patspark, could you please post reference documentation regarding this rule?

I now know that a visual inspection of the spare tire will not reveal very low pressure in the spare. Our spare was at 20 lbs. when it should have been at 60 lbs.

I have driven on a spare before with our other Prius, the 2006 model. It was also the front driver's side tire. I didn't have any acceleration and/or slip indicator light issues. Although the the spare may have been properly inflated and/or the slip indicator may have been configured differently.

So I guess we need to include a bicycle pump in our emergency kit in the back of the tire to inflate a low spare and have the tire center check and inflate the spare at every oil change?

-------
Update on May 5, 2015 (the next day).

Last night, about 8 hours after driving home, we checked the pressure of the tire. It was 21.5. It was supposed to be 35 lbs. We put more air in three times before driving back to Costco 24 hours later. The same mechanic looked at the tire and finally found a tiny hole in the side wall. He ordered a new tire so I'll have to go back in 2-3 days to have it replaced. The tread was still really good so the prorated amount for the warranty replacement was 0.00. They asked if I wanted the spare on the car or the leaky tire. I chose the leaky tire since I was worried I might have a repeat of the slip indicator light coming on. I'll just set my timer to go out and pump up the tire every 8 hours.

 

you should check and inflate your tyres once a month (see the manual), including the spare. if any tyre drops more than a few pounds in that time, you should have it serviced.

 

I had a tire with a slow leak in it a year ago. I had to put air in it every week. Some nights if the wheel was sitting on gravel a certain way it would empty out overnight. Just before fixing this problem I was driving about 50 mph on the highway around a corner and the car immediately brakes all by itself and I slow down to about 15-20 mph. It was quite scary. The yellow traction light also came on. Once the highway straightened up the light came off and the car drove normally. I took it to the nearest gas station to check the tires, and sure enough the problem tire was very low. Immediately fixed the tire after that. It was quite something it was like my Prius came alive and took over. I've never said an insulting word to her ever since, hehe.....

 

I just got a flat tire today front passenger side, I hit the curve a little the back tire was fine, I put the donut on the front tire I could not exceed 28 miles an hour and it got lower then that as well
Went down to 18mph, just happened tonight not sure if I want to try driving it to Town Fair tire replace the tire or have it towed to Toyota it is due for 150000 mile check out anyways