I have a question. I have a RX400h AWD and I noticed when you start up the vehical and it's in READY mode the gasoline engine would come on and idle for about 30 seconds and shut up. I was aware that this is just to warm things up. But is it suppose to do it on a hot start. Say like I drove the car about about an hr, I stopped to get gas and restart as the gas station it would come on again for another 30 seconds. It always behaved like this and I thought it was normal until I noticed a guy jumps in his 2nd gen Prius, turns on, plays with a CD for a second and drives off all on EV only.

Yesterday the car did something strange, the engine ilded for about 5 min the in driveway after a warm restart, A/C was off and battery was 80%, even the cooling fan came on a couple of times.

Also while the gas engine is on I notice a rattling noise coming from underneath the vehicle. Only while it's in park or Reverse, it stops when the engine stops and the sound is similar to a throw out bearing on a manual transmission car in neutral. Any advice, I just want to know if this is abnormal before I call the dealership.

The car has roughly 36,000 miles on it.

 

The power train is still under warranty. So if you were like me, you'd have called to set up an appointment. I'm still learning my 450h and not sure how yours is supposed to behave.

 

It is normal for the gas engine to run like that when you start the car it has to warm up the emissions etc. to a certain temperature. Mine does the strange run as you call it sometimes. The Prius is a totally different system than we have. I went from a Lexus LS400 to a Prius and now a RX400h.
The rattling noise underneath I do not know about I have 46,000 miles on my 2006. I would ask your dealer about it also.

 

You may want to try the procedure pasted down below which I found at

http://www.greenhybrid.com/discuss/f...fication-8126/

There is also a TSB

http://us.lexusownersclub.com/forums...=post&id=12947

(and other TSBs you may want to peruse here - http://us.lexusownersclub.com/forums...howtopic=58929)

regarding resetting the ISC (idle speed control) after the battery has been disconnected or run down. The TSB explains the process in detail, and the instructions involve using a Lexus diagnostic tester, HOWEVER, as long as you have driven the vehicle (with the engine running mostly - try not to drive on electric only before you park) so the temperature is 180 or more, the procedure at greenhybrid works fine. It seems that the Lexus tester is only needed to confirm the coolant temp is over 180.

I have done this procedure with no ill effects after purchasing my RX400h used (didn't know if the battery had ever been disconnected). My mileage went from 10.2 to 8.5 litres per 100km after doing the procedure. The only thing I found when I did the procedure, was that I could not get the power meter anywhere near 1/2 to 3/4 no matter how far I depressed it, otherwise everything worked as pasted below.


______________ISC LEARNING PROCEDURE __________________________________________

This applies to the 2006 Highlander Hybrid also.

Note that you can probably perform the procedure yourself.

The scan tool mentioned in the procedure checks the coolant temperature to make sure it is at full operating temperature and checks the engine loading to make sure the load is sufficient to charge the battery and finally checks the status of the ISC learning parameter. It is not necessary to monitor these parameters if you do the procedure carefully.

1) Make sure the vehicle is fully warmed up. Do the procedure immediately following a long drive that runs the engine (highway speeds are best - not long gliding stealth runs at low speeds with the engine off). This will insure the coolant temp is at FULL operating temperature - it is not necessary to actually measure the coolant temperature if you warm up the engine sufficiently and don't let the engine shut down too long and cool off before doing the procedure.

2) With the vehicle stopped and in drive, press firmly on the brake to keep the vehicle from moving and then step on the accelerator while watching the power meter (to the left of the speedometer). Press down on the accelerator to keep the needle between 1/2 and 3/4 up the scale. You will find that the engine management system will automatically limit the engine load no matter how far you press down on the pedal so the amount you press is not critical as long as it is either 1/2 scale or to the engine's self-limiting load value. Keep the engine loaded for a full 30 seconds but not longer than 40 seconds (this procedure brings the hybrid battery up to a maximum state of charge - if you watch the battery symbol, you willl see it tick up to a "full" display).

3) Shut off the engine and place it in park
4) Wait 5 seconds.
5) Turn the ignition key back on to display "ready"
6) make sure the A/C and heater system controls are set to off
6) Lightly step on the accelerator pedal until the engine starts -then immediately take your foot off the accelerator and let the engine run until it stops by itself.

This completes the procedure.

 

That is some good information. I just dropped it off at the dealer today. I wasn't able to duplicate the transmission noise at first but I notice it's more pronounced in reverse. I know my fuel economy isn't suffering. I usually can average 34mpg in city and 26-27 on highway

 

With that fuel economy you're ahead of the game. What are your driving conditions (route, miles, hills, stops, etc) and what octane do you burn ?

 

I use 89 octane.

The route is city driving stop light to stop light. There are a few up hills but the speed limit is sometimes 35-40mph. If I'm light enough on the throttle I can cruise for a few miles on EV only. I'm also medium on the throttle I accelerated up to the speed limit and try to be as light as possible on the throttle. On the highway I notice its hard to maintain 70 and still be efficient.