Last post on May 29, 2013 at 3:30 PM
You are in the Lexus RX 400h
What is this discussion about?
Lexus RX 400h, Fuel Efficiency (MPG), SUV
#349 of 358 Re: Sudden Change in Mileage [bocastephen]
Mar 09, 2012 (4:48 pm)
Thank you for this good description. After just purchasing a 2006 RX400h, you can imagine my disappointment driving on a road trip and seeing the mpg peak at 23. Mostly 22, and no different around town prior to the trip. I had done what I thought was the correct procedure according to the tsb, but I did not first drain the batteries as you state to do here. That made all the difference. Found this thread while at the hotel, and tried it the next morning... that second day of the trip, the average jumped 20%+ to over 27 mpg! Now I thoroughly love this car! It doesn't seem to make sense why this works, and is an odd quirk to the vehicle, but it certainly does make a big difference.
#350 of 358 2006 rx400h fuel economy change
Mar 10, 2012 (9:20 am)
I own a 2006 AWD RX400h, and have been the sole owner and driver. I am more of a highway or country/windy road driver as opposed to a city driver. I have never felt that I got the full benefits of owning a hybrid, but never complained with the 25-28 avg MPG (my previous vehicle was a Ford Expedition, which averaged 10-12). I am not a 'gentle' driver, but not an Indy racer either. In the past 2 months, my car has gone from the 25-28 avg to 18-20 MPG. With the 15 gal tank, where I used to avg anywhere from 320-360 miles per tank, I am lucky to get 260-280. I have not changed the tires in this time frame, I use the same gas, from the same station majority of time, which has always been the premium blend. Tire pressure is fine, and tires have been rotated at 5000 mile intervals... Nothing has changed!! I am just puzzled on the significant change in fuel economy. Yes, it is winter here in SW PA, but the temps have been quite mild compared to previous winters, and my car is garage kept the bulk of the time. Anyone have any suggestions or opinions as to this change? Thanks!
#351 of 358 Re: 2006 rx400h fuel economy change [cvav1615]
Mar 10, 2012 (9:38 am)
I would try an ISC reset procedure to reset the battery charging logic. I have copied the procedure from an earlier post. Here it is...
When you reset the ISC, you idle around and drain the battery until the engine comes on, then shut the car down. You turn off all accessories and climate control (nothing electronic should be on). Put the car in run mode (start it), press the brake pedal, put the car in drive, then while holding the brake pedal down, press the accelerator pedal down.
The car will not move or rev much, but the engine will be on and start charging. Keep the gas pedal down for 40 seconds, then release it for a few moments, then down again for 40 seconds and keep doing that 40 on/10 off etc until the battery is fully charged (all green) and the engine no longer charges or revs slightly when you press the gas pedal down. Of course you're holding the brake pedal down all the time while doing this.
Shut down, put your accessories back where you want them, then you can start up and go anytime. Learn about pulse driving to maximize your mileage going forward.
#352 of 358 Re: 2006 rx400h fuel economy change [skycaptain]
Mar 10, 2012 (10:32 am)
Thanks Luke, I will try this. Just one question, how will I know the battery is full, in the green, if I do not have the Nav screen on to show me the Hybrid system? Thanks!
#353 of 358 Re: 2006 rx400h fuel economy change [cvav1615]
Mar 11, 2012 (9:53 am)
Maybe the oil company changed the gas composition to be less polluting. Ethanol will reduce mileage.
#354 of 358 Re: 2006 rx400h fuel economy change [cvav1615]
Mar 11, 2012 (3:45 pm)
Cvav, You leave the screen on for this procedure so you see the Hybrid battery turn green....Good Luck!!....
#355 of 358 Re: Lexus 400RX Gas Mileage False AdMPG.
Oct 10, 2012 (2:31 am)
I just purchased a 2008 RX 400 H . the millage is great in city 25 mpg.
The problem with consumption is how you drive , when I am driving is 25mpg when my son driving is 19 MPG
#356 of 358 Re: 2006 rx400h fuel economy change [cvav1615]
Dec 25, 2012 (8:13 am)
Dear Luke: Merry Xmas! My Rxh 400 2006, died on me yesterday with two messages Check VSC and Hybrid system. Would the above procedue help me so that I can get it to the mechanic? I was supposed to take into the shop last week but scheduling got the best of me, the maintenance required light went on and with the holdiays couldn't get there. My car and I have been through alot and its been serviced regularly "old blue" has been through many a bad snow storm and icy roads and has been pretty good on the mileage too.
Alice And Happy New Year All!
#357 of 358 Re: 2006 rx400h fuel economy change [skycaptain]
Jan 04, 2013 (7:01 pm)
About how long does it take to recharge the battery while doing the 40on/10off? Just bought a 2008 rx400h and the mileage is lousy and I've been really conservative in my driving.
#358 of 358 Re: Lexus 400RX Gas Mileage False Advertising [tmtanalyst]
May 29, 2013 (3:30 pm)
If you live in a cold weather climate the gas companies change the make up of the gasoline to aid starting in cold weather. This gas reduces the mileage on most vehicles and especially on hybrids. September is the month when cold weather gas is introduced and ends in May. I had a Prius and I got 51 mpg I summer and it went down to 41 in winter.