Instruments and Controls Identification charging system and batteries checked at a repair facility. the LED miles per gallon display for 60 seconds. An "F" appears in the display together with the fault code, for example "F37." If the engine sends a single fault code, the display blinks on and off for 60 sec- onds while displaying the code. It then goes back to displaying the MPG. If the engine sends more than one fault code, the display blinks each fault code on and off three times and keeps repeating them for 60 seconds. It then goes back to reading MPG. To find out the engine problem, look up the displayed num- ber in your engine fault code list.
On a vehicle equipped with a battery isolator system, the voltmeter measures the average voltage of all of the batteries when the engine is running. When the engine is stopped, the voltmeter shows only the gel cell battery voltage and does not indicate the voltage of the engine-starting batteries. CAUTION Gel cell batteries can be damaged if the battery voltage is allowed to drop below 12.0 volts or if the charging voltage is more than 14.1 volts. Start the engine to recharge the gel cell before the battery becomes fully discharged. If an exter- nal charger is needed, disconnect the gel cell battery and use only an external battery charger that has been approved for gel cell batteries.
If you need to review the fault codes received, simply press and release the "Reset" toggle switch to dis- play the fault code history file. The display shows "h" plus each fault code starting with the most recent, for example, (h13, h27, h17). Each code blinks three times before showing the next code. After showing all of the codes, the display shows "- -" and then goes back to displaying MPG. If there are no fault codes in the history file, the display blinks "- -" four times and goes back to showing MPG. The history file may be viewed at any time. Fuel-Tach Gauge, Optional The FloScan Fuel-Tach ( Fig.
2.27 ) is an electronic monitoring system that records fuel consumption and displays average miles per gallon. The Fuel-Tach provides you with immediate feedback showing a percentage difference between the current fuel con- sumption rate and the total trip miles per gallon aver- age. If there are multiple active fault codes, they are sent sequentially by the engine databus. The sequence repeats as long as the faults are not corrected. Any code appears in the history file only once even though the sequence of codes is repeating.
If you view the history file several times in a short period of time, the order of the codes may change depending on which code of the repeating sequence was sent most recently. The "0" point on the gauge means that the current fuel consumption rate is the same as the miles per gallon average of the total trip distance traveled. Clockwise movement (into the green zone) of the gauge needle shows the percentage improvement in the current fuel consumption rate compared to the miles per gallon trip average. Engine Hour Meter, Optional An engine hour meter records continuous operating hours of the engine and is mounted in the control panel.
In cases where actual mileage does not indi- cate overall usage, maintenance and lubrication in- tervals for the engine and engine-operated equip- ment can be determined by operating hours. Counterclockwise movement (into the red zone) of the gauge needle shows that the current fuel con- sumption rate is higher than miles per gallon trip av- erage. Needle movement into the red zone means that the driver should shift the transmission or change vehicle speed to increase fuel efficiency, as driving conditions permit. Application Air Pressure Gauge, Optional An application air pressure gauge ( Fig.
2.27 ) regis- ters the air pressure being used to apply the brakes and should be used for reference only. The gauge will not register air pressure until the foot brake pedal is depressed or the trailer hand brake is applied. The Fuel-Tach system is operated by a toggle switch. For switch operating instructions, see "Fuel-Tach Switch" in this chapter. The Fuel-Tach system installed in vehicles with elec- tronic engines also displays fault codes correspond- ing to any engine problems that might occur. When the engine databus sends a fault code, it interrupts 2.27