Hi, I'm looking for feedback from folks who have a 2004-07 Prius about driving in ice and snow. There are many reports of problems with traction control stopping all progress rather than spinning the tires. Use of chains and snow tires may help. Anyone have any updates on this? Thanks, Bob Wilson ps. Living in North Alabama and driving an NHW11 means I don't have many opportunities to test this.

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I have an 04 and I live in Colorado Springs. Never had this problem. In fact, my Prius is the best snow car I've ever driven in my entire life, and that's with all weather tires.

Infael

2004 Gray Prius with smart start/entry and VSC

Bob,

I had difficulty getting up my driveway with the Goodyear Integrity and my Michelin MXV4+ tires in bad weather for 3 winters due to a combination of poor tire grip and the so-called Traction Control in my 2004 Prius. This year I had no problems with the traction control as My Nokian WR tires are wonderful in wet/slush/snow/ice. Just make a strong recommendation for good tires (either Snow/Ice or the Nokian WR or WRg2) if confronted with bad driving conditions.

JeffD

Is this something that just front snow tires is enough or do all four wheels have to be the same tire?

Bob Wilson

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You need to have similar traction on all four wheels. Especially you do NOT want lower traction on the rear wheels. You will spin and not be able to see or avoid whatever you are spinning into!

I "threw away" the nearly new stock Goodyear Integrities last October, and put on Nokian WR "real" all season tires. I had no problems this winter. In fact, last weekend we had a blizzard. I drove on a 70 km/hr or 45 miles per hour highway and didn't slip once. That can't be said for many other drivers - passed by one clutch of 10 cars that slid together in a cluster and another full sized PU that spun into the median. Even the new Blazer ahead of me would spin up his rear wheels and slide sideways 2-3 ft every time he started. MORONS! He had 4WD and didn't even bother to engage it, hence was sliding on the ice/snow! All this in just two miles of road!

This drive DID drop my mileage average, of course. But not because of the Nokians. They didn't decrease the cars' mileage at all. It's was the short trip.

Pearl is a
2007 Driftwood Pearl Prius
Package "B" (everything but leather, nav, and rear camera)

I seem to be the only person that had experiences with both TRAC setups on the same car.

Here's the background info in case you haven't been following me on PriusChat:

2005 Prius bought in Oct 04.

The first winter, I got stuck pulling out of the curb. We had a good 10-15cm of snow. I decided to test the Prius' TRAC since it's the first winter and snow events around here (esp. with 10+cm) are few and far between (they usually melt within days). As expected (at the time), the wheels spun and the TRAC cut all power. No amount of prodding on the acccelerator would produce any forward movement at all (can't imagine rolling on momentum if the power was cut while making a left turn).

Anyway.. that was my one and only time with the TRAC cutting all power. Next year (winter 05/06), there was that ECU update. My Prius tech fried my engine ECU so my poor car was at the dealership for a week and a bit.

I found out the TRAC changed its behaviour by accident actually. I was backing into the garage (we're on a slope) and I noticed this weird sound... it was like the engine was revving up and down. I thought it was weird but figured it was the TRAC doing its thing. Then I noticed the blinking Slip Indicator. Ok, so it was TRAC. I had regained grip by then so I ignored it. I knew it was a bit icy in the alley. So I continued to back up and then it happened again. It was then it strucked me. The tyres were spinning! I stopped the car then intentionally tried to get the wheels to spin and it did. The engine was just revving up and down as the power was fed in pulses by the TRAC in an attempt to regain traction.

I posted my findings online and we couldn't figure out why I had the old "cut all power" TRAC behaviour before and now it was exhibiting the "slip and grip" behaviour. I thought it might have something to do with the ECU update but a wife of a Prius tech said her DH wasn't aware of any changes done to the TRAC.


I hope you can delve deep into this issue and maybe find out how I managed to get it changed and help those that have the old TRAC setup, update to the new one.

Mods: EV mod, VVT-i emblem, sport pedals, OEM cargo mat, JDM Prius interior footwell lighting, DICE iPod kit, OEM all-weather mats, LED licence plate lights, Phillips Vision Plus

Bob,

I have the WRs on all four wheels which is the best thing to do as they are all-weather tires that work as well as most snow tires in bad weather. The improved traction to get up the driveway only requires good tires on the front, but as discussed below, mismatching tires is not a good thing in general.

JeffD

Hummmm, I'm not sure how to write this up. Feel free to update this rough draft:

In very slippery winter conditions, limited to 2004-2007(?) model year Prius with OEM or non-winter tires, the traction control avoids spinning the tires and can leave the car immobile. Those in snowy, winter climates should mount quality ice and snow tires in the winter season. More recent Prius or those whose ECU was flash upgraded(?) have an improved traction control that will 'pulse-spin' the wheels in super slippery, icy conditions.

Is this about right or do we need more?

Thanks,
Bob Wilson

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Bob,

The tires should have the Winter tire emblem (a snowflake in a mountain) which is on many (all?) winter tires and a small number of All-Weather tires (eg the Nokian WR).

The ECU upgrade that "Fixed" the hesitation problem is a confused issue. In Tideland's case the ECU was actually replaced so a re-flash may not be sufficient. His was replaced in late 05 or early 06 so the 2007 Prii (and late 2006) probably have avoided this issue (but I haven't seen any definitive data).

Note that this also causes me to be very careful when merging into traffic as a tire slip on sand or loose gravel can cause enough hesitation to get into an accident.

There are very few design problems in the 04-05 Prius, but this one is significant (the Guess-Gauge and gas tank bladder is an aggravation, but I can deal with it).

JeffD

How about this:

In very slippery road and winter conditions, the 2004-2006 model year Prius with OEM or non-winter tires, the traction control can leave the car unresponsive even with the accelerator pressed to the floor. It does this to prevent useless wheel spinning. Those who live in snowy, winter climates should mount quality ice and snow tires (marked with a snowflake in a mountain) in the winter season. More recent Prius ECUs have an improved traction control system that will 'pulse-spin' the wheels in super slippery, icy conditions.

Bob Wilson

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