lanenavyrn

I have a 2012 AWD RX350. In order to put the car in snow mode i have to manually select it which is fine BUT when I turn off the car and then restart I have to manually put it back in snow mode since it resets itself when turned off. Is there any memory system that will always keep it in snow mode? Also, is snow mode the only time the AWD is enabled or is it always enabled and I just am confused? Thank you.

AL13NV8D3R

Awd is always active reguardless of snow mode is on or off. The awd system on the RX is front wheel drive bias and in most conditions will send most of the power to the front. When the front starts to slip awd can send up to %50 power to the rear wheels.

Snow mode is mostly for transmission software change. What it does is starts the car in second gear to avoid wheel spin off from a stop while accelerating. Therefore the system must reset to normal mode when car is turned off. Driving all the time in snow mode is not a good idea because it will wear down your transmission because it always make you car start in second gear. There is a reason all transmissions have first gear.

vlad_a

Here's some good info about snow mode:
https://www.clublexus.com/forums/rx-...he-snow-3.html

2nd gear starts is an old-wife's-tale. People have been making this claim for years in the IS forum, yet the '01 Auto IS300 I owned started in first just fine in the snow mode. Some used Snow mode as an Eco mode.

In short, you get decreased throttle and more AWD engagement. It turns itself off so people wouldn't forget to. Generally, you wouldn't need to run it on regular basis as roads get cleared pretty fast.

raylor4

Thanks vlad,
Well said. It all makes sense the way you explained it.
Ray A.

In short, you get decreased throttle and more AWD engagement. It turns itself off so people wouldn't forget to. Generally, you wouldn't need to run it on regular basis as roads get cleared pretty fast. vlad

SC300Star

Too bad they don't make the fog light switch that way...

vlad_a

Thanks, Ray!

hypervish

No, it's no folk tale.

At least not on the first generation RX. They do in fact start off in 2nd gear, when SNOW mode is engaged. Not sure about the 3rd generation though.

vlad_a

May I ask how you came up with that conclusion? Because same claims are made for 1IS every time it snows, and mine did 1-2 shift just fine (many moons ago). It is slower to respond, hence why people believe that 1st gear is not used. In reality, it makes no sense not to use the 1st gear... at least not to me. Especially on a 4-gear auto that the RX300 is. 2nd gear is too tall to start from a standstill.

hypervish

The RX300's transmission programming instructs it to shift into neutral when slowing down to about 15 mph, T/L did this to improve mpg (there were claims of an 8% increase). Anyways, this can lead to excessive shifting and premature transmission failure. For example, if you are slowing down because the light is red (and the car is going into neutral), let's say the light turned green, you got back on the throttle hard. The transmission is now having to shift back into gear, and in a very harsh manner.

Anyways, the point of the above was that I like to avoid this scenario by using snow mode. So if I am approaching a light, and I think it's going to turn green soon, I'll coast and enable snow mode. This keeps it from dropping into neutral. So as soon as I get back onto it, I can tell that it's in gear and not in neutral. Because if it were you can feel a slight slingshot effect as the transmission gets back into gear.

Secondly, as you mentioned 2nd gear is a bit tall. However, not so tall that you can't accelerate. If you enable snow mode from a standstill, you can tell the difference as opposed to accelerating without it on. The engine of course revs up more when in snow mode to get going.

Thirdly, the manual quite bluntly states that the car starts off in 2nd gear.

vlad_a

Can you do this:
1) Turn snow mode on
2) Floor it from the standstill
3) Count number of shifts until you hit 40MPH+ and back off the throttle

Repeat the same procedure with the shifter in 2 until 30MPH. Then do the same in L until you run out of RPM range.

Also, if you can find where in the manual it states that the snow mode starts are not using 1st gear, that would be awesome. lexusdrivers.com
I've been chasing this confusion for years and need some solid facts, as I don't have any vehicles that I can test it on.

hypervish

LOL, no.

I think i have provided plenty of solid information that the car starts in 2nd gear when in snow mode. And, like I said, the manual states it on page 318.

vlad_a

I am sorry, but rolling start is not a start from a standstill, therefore it is inconclusive.
I do not have an RX300 manual, so I can't look up page 318. Thanks anyway.

hypervish

I also said that you can notice it from a standstill.

You can view the manual online from the Lexus website, but I will provide a screenshot here. Also, here's some screenshots from a Technical Description file on the RX300 that further prove snow mode starts in 2nd gear.

If this isn't enough, then well, I'm sorry.

vlad_a

Here's all it states for the IS300:
You can select the snow mode by pushing the ”SNOW”
switch. The ”SNOW” indicator light will come on.
Snow mode:
Decreases the engine output to minimize rear
wheel spinning on snowcovered or slippery roads.
To return to the normal mode, push the ”SNOW” switch again.
The ”SNOW” indicator light will go off.
When you turn the ignition switch off in the snow mode, the
mode automatically changes to the normal mode.

Unfortunately RX350/450h manual has about as much info.

vlad_a

Thanks, mate! This is brilliant!