Isc Learning Procedure (without Lexus Diagnostic Tester)

[mike5100]

Just thought I would update this thread.

Three tanks after picking up the car from Lexus dealer after new battery fitted.

28.5 mpg, 28.6 then 28.1 (real mpg's calculated by filling the tank and zeroing the tripmeter)

Did the ISC learning procedure as described without the diagnostic kit.

First tank 29.1 mpg second tank 28.1 mpg

All are UK gallons and all tanks except the best one were my normal driving pattern for the week. The other one was a run to London on the A1 at 70-75mph

The cars computer consistently displayed about 1mpg better than reality.

Mike

[Witty9]

My RX400h was at the dealer for a recall issue when they recommended a new 12V battery. I went ahead with replacing it. Immediately afterwards, my around-town mileage dropped from ~28 mpg to ~24 mpg. Since it was winter, I thought it might just be the cold. But the consistent lower mileage persisted even after the weather warmed up.

I discovered this thread about the ISC "learning procedure" and I did it today while the car was fully warm. It's a strange sequence of things to do, but I followed the instructions very carefully. Immediately afterwards, my wife drove us around about 30 miles of mixed driving and got over 30 mpg! I drove it, and still got over 28 mpg. The car seems back to normal. I know this car is more muscle than Prius, but I appreciate the little bit of extra efficiency.

If the dealer replaced the battery and did not run this procedure, I feel they should be faulted. On the other hand, they changed the battery during a bitterly cold winter, and it might have been difficult and inconvenient to get the engine fully hot. Incidentally, I also had to reset all my tire pressure limits myself, first deflating all my tires, setting the lower pressure limit, and then putting all the tire back to the pressure I like. I must say that replacing the battery is a pain on this car!

Thanks to all for this useful thread.

—Carl

[JamilUK]

Hi

I’ve had my rx for about 6mnths now. I recently found out there was an inverter recall outstanding on the car and so it went to the dealership. Whilst it was there, I had the battery replaced. Since getting it back a week ago, my mpg has dropped drastically (from approx 30mpg to 20mpg).

I’ve found this thread about the ISC reset and tried following the steps, but no improvement. I will try again but I have some questions so that I can be sure I am doing it right:

1. How far did you all drive to get the coolant temperature up? I did approx 10miles with speeds of between 40mph – 60mph for most of this.
2. After flooring the pedal for 30-40 seconds, I put it into park, put on the parking brake and turned the car off. Is this right or should I leave my foot on the brake pedal until the procedure is complete?
3. Lemon refers to an arrow from the engine to the battery being an indicator that the procedure has worked. Does this display after lightly pressing the accelerator? And is this arrow on the consumption screen in the centre console or on the little display behind the steering wheel? (That question must make me sound clueless about this car – probably because I am!).

Any answers to these questions will be much appreciated. I love this car, but if I can’t get the mpg back to where it was then I won’t be able to afford to run it anymore. I work out I’m losing something like 120 miles per tank at the moment.

Thanks

[Rajmirch]

i did this after 1 week of owning my 06 RX400h as i found i couldn't do more than 1mm of gas pedal movement before the engine kicked in!! After doing it i was able to get upto 25mph on electric!!! That's exactly what i needed as driving in London in rush-hour is normally start crawl stop start crawl stop!!

my dash is reporting 23.9-24.1 mpg on average but i'm still working my way through my first tank of petrol

 

Raj

[ktmrider]

Just got a 2007 400h last month, mileage was showing 20ish.

 

Found this thread then noted the 12v battery was relatively new.  Did the reset, mpg up to 26+ now!  Thanks a million sir.

[dta20502]

On 3/12/2011 at 7:12 AM, RXREY said:

I couldn't get the needle to do that either but it worked.

Me too with 2015 Es300h, the needle did not move at all when I floored accelerator pedal!

[DutchDave]

First of all, how awesome is this owners club. Here I find myself, in the Netherlands, following and celebrating the instructions someone called Lemon found and shared 12.5 years ago. If that doesn’t warm your heart a little, I don’t know what will. Lemon, wherever you are, I hope you are well. Also: I take my hat off to the administrators and moderators running this amazing bastion of knowledge. Thank you for making and keeping valuable information like this accessible to people like me.

About a  month ago I bought a 2006 RX400H. In almost pristine condition, owned by the first owner for thirteen years and then for another two years by his son. It had 222k km’s on it, about 140k miles. It is black with a light interior, just how I like it. And for a little over € 9.000 (about $ 10.000) this seemed to be a good deal. 

Unfortunately, I too was experiencing the quick awakening of my engine at even the slightest touch of the gas pedal. And I too was very disappointed about the efficiency. In (most of) Europe we use Liters per 100 km and I was getting around 10 liters per 100 km which is about 24mpg. I know I should be able to get at least 28mpg, which would display in my RX as 8.4L/100km. Considering we pay about €1.95 per liter over here ($10 per gallon!), any improvement in efficiency is obviously more than welcome.

So I searched the web in 4 different languages and I finally ended up here. Did I mention the awesomeness of this owners club? 

Two days ago, I came home in the evening after a half an hour drive and figured the engine would be warm enough to perform the ISC learning procedure. I had tried it twice before but it hadn't worked. I could not get the battery fully charged within the 40 second time frame. So I thought I would try it one more time and if it didn't work I would disconnect the 12V battery for a couple of minutes and then perform the procedure again. I turned the ignition on, switched off everything, lights, climate control, radio, mirror, anything I could switch off and put my left foot on the brake and switched it to drive. I stepped on the gas pedal. The engine revved up a little, the power meter hardly moved, so I floored it. The engine did not rev up any more and the power meter was still not moving. The battery did charge but after 40 seconds the symbol did not fill up to the top. It was still one green bar shy of full. I got a little worried. "What if the battery pack is bad? Did I buy a hybrid lemon? I did didn't I? I am such an idiot. I should have bought that CR-V." So I turned off the ignition and shook my head.

I waited a couple of seconds, got myself together and tried again. This time, I went all in. "If this RX is bad and you got screwed you might as well know the truth right now. But this is a Lexus. Have some faith. Stop being so !Removed! carefull and show this baby who's boss. She's a Toyota, she can take it." I said to myself. I ignored the power meter and just floored the gas pedal, concentrating on the charging of the hybrid battery. "Come on you Japanese miracle of engineering you! You can do this! Time has nothing on you! You are a Lexus! It's just a battery! Just fill it! Push Baby, Push! Do it!" I yelled at the screen. This probably did the trick because after about 10 seconds the final green bar showed up. So far so good. "You are doing great baby! I love you!" The power meter still had not moved but I kept the pedal down to get to 35 seconds on my iphone stopwatch and then put it in park and shut off the engine. I waited 5 seconds and turned the ignition key back to display 'ready’. I stepped lightly on the gas until the engine started. I was feeling very confident. 

The first minute or so the engine ran steady at a normal RPM. Like nothing happened. My confidence got a little less sturdy. But then I could hear some 'robocop' stuff going on and the engine revved up just a little for about 15 to 20 seconds before it returned to the normal, lower RPM. It ran for another minute or so and then it stopped. In total it ran for about three or four minutes.

Today, after a little under 100 kilometers (60 miles) of driving through mainly the Dutch countryside, my display shows 8.8L/100km (27mpg). I know it is just a short distance and it is a bit thin to base any conclusions on, but I have no doubt that the procedure has had an effect. Before my average has not been under 9.9L/100km (24mpg). And the car feels different. Like it just had a service job or something. It seems smoother and more responsive. 

In the unlikely event that I am not the last person to ever visit this topic and some other newbee '06 400H owner is wondering why his or her new old hybrid is so thirsty and ends up here, I just have to add three things to all the instructions already given in this topic: 

1. Forget about the power meter, just floor the pedal and focus on getting the battery fully charged. Preferably let it charge a little even after the final green bar has appeared. 

2. If you don't hear the engine change RPM's in the first two minutes after the restart, your RX is not learning anything. Just start over.

3. Yelling positive and motivational things will help. But you have to really believe it. Not just say it. 

 

[HaloRomeo27]

There is two systems on the 400h that would need reset one is the hybrid learning which does require a tool and the other is the ICS most of the late 07 and 08 will do it automatically there was an ECM update for those