[jdenenberg]

bwilson4web said:

I do not have an NHW20 to test but I believe a ScanGauge with the diagnostic XGAUGEs would be an excellent choice. There is nothing worse than to be on a trip and have an error light come on and no way to read out what is going on . . . like having a flat tire and discovering your spare is flat too.

I had a problem with my 2004 Prius in Urbana Illinois. It refused to go into "Ready" and my ScanGauge said "No Codes". Steve at AutoBeYours had me reset (disconnect the 12v for a few minutes) to get it running so I could drive to southern Indiana. He found that a sensor connector to my ReInVolt Battery was not fully clicked home, charged me $40 and gave me a nice T-shirt.

The ScanGauge doesn't read HV ECU codes! Steve's Toyota scan tool was very effective (as it should be). I was surprised and disappointed in this ScanGauge (version 4.02) limitation.

JeffD

[bwilson4web]

jdenenberg said:

. . .
The ScanGauge doesn't read HV ECU codes! Steve's Toyota scan tool was very effective (as it should be). I was surprised and disappointed in this ScanGauge (version 4.02) limitation. . . .

I have to use XGAUGEs to read my NHW11 battery, HV, and engine diagnostics codes. The default scangauge reads just the 'emissions' related codes. Sad to say, I don't know if the NHW20, XGAUGEs include the diagnostic codes . . . I've just never looked.

The ZVW30 will put me at the 'bleeding edge' which will offer unique challenges.

Bob Wilson

[Mckenzie500]

LLC scanner can also be used and OBD, a computer based system keep a track on emission levels in the vehicles and more.

[billysbarn]

Hi Bob
Very busy here these days, so haven't been back to you! Sorry!
Well, I am baffled by my readings from SG2. The MPG readings are considerably different to the RX400 own readings on the screen. Eg. SG2 could read average 23 mpg when the car is showing an average 34 mpg for a journey
Any ideas why? Could part of the problem be due to the difference between UK ans US gallons? If so is it possible to set it to UK gallons?
Also, I typed in the XGauge values from one of the spreadsheets, (I think it was yours) for the HV battery voltage and amps and another that I can't remember just now. But none of the values gave a reading, so I guess the Lexus codes are different to the Prius?
What do you think?
Thanks
Billy

[bwilson4web]

billysbarn said:

Hi Bob
Very busy here these days, so haven't been back to you! Sorry!
Well, I am baffled by my readings from SG2. The MPG readings are considerably different to the RX400 own readings on the screen. Eg. SG2 could read average 23 mpg when the car is showing an average 34 mpg for a journey
Any ideas why? Could part of the problem be due to the difference between UK ans US gallons? If so is it possible to set it to UK gallons?

Let's do the math:

1 Igal = 1.2 USgal
34 / 23 = 1.47 . . . close but not exact

billysbarn said:

. . .
Also, I typed in the XGauge values from one of the spreadsheets, (I think it was yours) for the HV battery voltage and amps and another that I can't remember just now. But none of the values gave a reading, so I guess the Lexus codes are different to the Prius?

Sad to say, that is very likely.

billysbarn said:

. . .
What do you think?
Thanks
Billy

I think the first step is to contact ScanGauge directly and report your problems and symptoms. They may not be able to help on the Lexus codes BUT they should have a recommendation on the MPG problem.

Are you able to get good data on:

1) coolant temperature
2) gallons per hour (just a fuel consumption metric)
3) engine rpm

These three are the most useful metrics for efficient driving and I'll explain why.

COOLANT TEMPERATURE

We know the Prius has some warm-up states that control what the car does. I don't know that anyone has mapped Lexus hybrid behavior so you may be at 'the leading edge.'

Here are some things you need to test:

1. When the car is cold and you start out in the morning, can you find a constant rate of fuel consumption as you accelerate? - The Prius, even my 2003 Prius, will accelerate at a fixed fuel consumption of 0.60 gal/hr for 45-50 seconds in the NHW11 and nearly 210 seconds for both the NHW20 and ZVW30. I regularly reach 35-40 mph on a cold start with my NHW11 before this 'extended EV' mode goes away. It means if you can reach a reasonably fast speed in this "EV" mode, you can get excellent MPG until the car has to slow down and complete the warm-up.
2. Do you have to reach 70C before the engine will stop when the vehicle is stopped? - Both my ZVW30 and Ken@Japan's NHW20 do. But my NHW11 does not 'autostop' until it at least reaches 70C. We need to know if your Lexus does the same. If not, there may be a software fix from Toyota to enable this early, 'autostop' at lower than 70C.

GALLONS PER HOUR (fuel consumption regardless of load)

This is important to verify what happens when the car is in "idle" or "N" and the engine still runs. This is your primary indicator of fuel consumption REGARDLESS of speed. One of the easy tricks is to shift into "N" and see what happens. The engine will continue to run but see if the gallons per hour goes down. . . . neat trick, yes?

ENGINE RPM

Although difficult to plot accurately, engine rpm is one of the best power and fuel consumption indicators. I can not help you map it on the Lexus but if you keep a weather eye on it and gallons/hour, you may find a "knee in the curve." You may figure out that there are specific rpm regions that if you stay below them, the car is a fuel miser and above . . . a fuel Bacchus.

Bob Wilson

[billysbarn]

Thanks for that Bob
I will try out those ideas.
re: 1) coolant temperature, I will have a look see. I can't do it this morning as I have already plugged in my Kenlowe engine heater which makes a big difference to the start up mpg.
2) gallons per hour (just a fuel consumption metric) Yes I saw that yesterday. The lowest seems to be 0.04 GPH when the engine is off/
3) engine rpm Yes. that is working ok.
Gotta dash now to meet a bus.
Thanks
BVilly

[bwilson4web]

billysbarn said:

. . .
re: 1) coolant temperature, I will have a look see. I can't do it this morning as I have already plugged in my Kenlowe engine heater which makes a big difference to the start up mpg.
. . .

Big thumbs up on the engine heater!

Bob Wilson

[billysbarn]

Yup