Confused Km-Age Range Computation ? Zero At Quarter Tank

[Gamma]

Last night, the mileage (km-age) range guide suddenly changed from 17km to 0km. Almost crapping myself at the thought of being stranded without gas, I quickly located a petrol station and filled up about quarter tank. Usually, the km-age range updates itself after a couple of minutes but after driving almost 30km and still with a quarter tank, the range km-age still shows ZERO...(see pic). Has this happened to any of you guys ?

Gonna call up Lexus to get resolution.

[LEX51S]

What was the outcome of this. Fuel level sensor?

[Lexus Nerd]

The behaviour is normal for a CT 200h.

For any vehicle, you can accept that there is a certain amount of reserve fuel that won't be included in the "cruising range" calculation. Normally, it's a relatively small percentage of the fuel tank (e.g. for IS 350, 10 L/65 L tank = 15%, which would be reasonably close to the "E" line on the meter). But the CT only has a 45-litre tank.

The following is taken from the CT Owners Manual (US edition):

"When the vehicle has run out of fuel and the hybrid system cannot be started, refuel the vehicle with at least enough gasoline to make the low fuel level warning light go off. If there is only a small amount of fuel, the hybrid system may not be able to start.
(The minimum amount of fuel to add to make the low fuel level warning light go out is about 3.1 gal. [11.8 L, 2.6 Imp.gal.], when the vehicle is on a level surface. This value may vary when the vehicle is on a slope. Add extra fuel when the vehicle is inclined.)"

Now, 11.8 litres out of 45 litres is 26%. Hence, cruising range is said to be 0 when the tank is 1/4 full.

Of course, 11.8 litres would normally get you well over 200 km on the highway in a CT. But I guess the reserve level is rather high, just in case there's a problem with the hybrid battery.