06 Rx400h Cold Weather Mileage

[fox4]

I seem to forget from winter to winter (I live in the Chicago Area) how bad the cold weather mileage is on my 400h. It's not all that great in the summer (about 26 highway), but winter seems low for both city anf highway. Yesterday, I drove to Springfield, IL round trip. Temp was about 28 degrees. Road dry heading down there at 67 mph. Had a retired State Trooper with me who suggested I "take it easy - we're not in a hurry." Aside - Cruise control set at 70, but the actual speed is 3 mph less. Lexus will not fix it. Told me +/- 3mph is within specs. At 67 mph the 175 mile trip indicated 22.2 mpg.

The return trip in blowing snow and other assorted crud on the road at about 60 mph indicated 23.2 mpg. Local trips have been about 19 mpg. Car handled great with both dry and wet road conditions - no complaints at all. Anyone in a cold climate have better, similar or even lower averages?

Stu

[Barefoot Bob]

I seem to forget from winter to winter (I live in the Chicago Area) how bad the cold weather mileage is on my 400h. It's not all that great in the summer (about 26 highway), but winter seems low for both city anf highway. Yesterday, I drove to Springfield, IL round trip. Temp was about 28 degrees. Road dry heading down there at 67 mph. Had a retired State Trooper with me who suggested I "take it easy - we're not in a hurry." Aside - Cruise control set at 70, but the actual speed is 3 mph less. Lexus will not fix it. Told me +/- 3mph is within specs. At 67 mph the 175 mile trip indicated 22.2 mpg.

The return trip in blowing snow and other assorted crud on the road at about 60 mph indicated 23.2 mpg. Local trips have been about 19 mpg. Car handled great with both dry and wet road conditions - no complaints at all. Anyone in a cold climate have better, similar or even lower averages?

Stu

I have the same year,make and model. I live in southern Minnesota so I get that same weather. I have found the same issues that you have. When its cold out it seems the engine has to run that much more so the milage is down. I did however find out that in summer keeping the speed down at 60mph or below the milage gets alot better. That is unless you have one heck of a tail wind then its fine to run a bit faster.

[lemon]

I hate to sound like a broken record, but IF you have a 2006 and IF you have ever disconnected, replaced or run your 12 volt battery below 7 volts, you have to have the Idle Speed Control Learning Procedure done.

See here

http://us.lexusownersclub.com/forums/index...showtopic=58930

You can take it to the dealer, or try the DIY method, which I did and it worked like a charm. This was summer just past, and my mileage went from about 10 l/100km to 8 l/100km (dunno what that is in US MPG).

However, I will concede that once the cold weather arrived (in conjunction with the winter gas, which also negatively affects mileage) my mileage has crept up to about 9.6 l/100km.

So if you do the ISC learning procedure, you may not experience a dramatic increase in mileage because of the cold. However, you may see an increase in that 26mpg you were getting in the summer.

Other's who have done the ISC learning procedure have also noticed an increase in mileage. Another side benefit is you will hear less 'clunking/rattling' from the transmission while the vehicle is parked and idling when you first start it (that clunking/rattling noise is normal by the way).

[mk0099]

I hate to sound like a broken record, but IF you have a 2006 and IF you have ever disconnected, replaced or run your 12 volt battery below 7 volts, you have to have the Idle Speed Control Learning Procedure done.

See here

http://us.lexusownersclub.com/forums/index...showtopic=58930

You can take it to the dealer, or try the DIY method, which I did and it worked like a charm. This was summer just past, and my mileage went from about 10 l/100km to 8 l/100km (dunno what that is in US MPG).

However, I will concede that once the cold weather arrived (in conjunction with the winter gas, which also negatively affects mileage) my mileage has crept up to about 9.6 l/100km.

So if you do the ISC learning procedure, you may not experience a dramatic increase in mileage because of the cold. However, you may see an increase in that 26mpg you were getting in the summer.

Other's who have done the ISC learning procedure have also noticed an increase in mileage. Another side benefit is you will hear less 'clunking/rattling' from the transmission while the vehicle is parked and idling when you first start it (that clunking/rattling noise is normal by the way).

Thanks for the post. I just bought 2006 RX400h last week and drove it for 250 miles. Average was 23 mpg (10.23 l/100 km) and I will try the learning procedure soon to check the difference in efficiency. Weather here is almost summer (temperature is 16-25 celsius degrees). Thanks for the procedure.

[mk0099]

26 mpg for two fills after the learning procedure. I also get used to the car and my driving is more suitable for the hybrid now.