Instruments Fuel/Diesel Exhaust Fluid (DEF) Gauge, EPA10 and Newer Air pressure gauges ( Fig. 3.4 ) register the pressure in the primary and secondary air systems. Normal pressure with the engine running is 100 to 120 psi (689 to 827 kPa) in both systems. The fuel and DEF levels are measured in a dual pur- pose fuel/DEF gauge. See Fig. 3.3 . 1 5 2 4 3 05/14/2001 f610556 11/09/2009 f611046 1. Diesel Fuel Level Indicator 2. DEF Symbol 3. DEF Level Indicator 4. Low DEF Warning Lamp (activates below 10% DEF) 5. Low Fuel Warning Lamp (activates at 1/8 tank of fuel) Fig.
3.4, Air Pressure Gauge (reservoir A shown) A low air pressure warning lamp and audible warn- ing, connected to both the primary and secondary systems, activate when air pressure in either system drops below a minimum pressure of 65 to 75 psi (448 to 517 kPa). Fig. 3.3, Fuel/DEF Gauge, EPA10 and Newer Vehicles When the engine is started, the warning lamp and audible warning remain on until air pressure in both systems exceeds minimum pressure. The diesel fuel level is indicated at the top of the gauge, with a low-fuel warning lamp that illuminates when the diesel fuel level registers 1/8th of capacity. Speedometer The DEF level is indicated in the lightbar on the lower portion of the gauge.
There is a low DEF level warning lamp that illuminates amber when the DEF level reaches 10% of capacity. See Chapter 11 for details of the DEF gauge functions. Three speedometer face options are available. The U.S. version of the speedometer ( Fig. 3.5 ) registers speed in both miles per hour (mph) and kilometers per hour (km/h), with mph in larger numbers. The metric version of the speedometer face reverses this arrangement, with km/h in larger numbers. The metric-only version, installed on vehicles bound for Australia, shows km/h exclusively. Primary and Secondary Air Pressure Gauges WARNING Tachometer The tachometer (see Fig.
3.6 ) indicates engine speed in revolutions per minute (rpm) and serves as a guide for shifting the transmission and keeping the engine in the appropriate rpm range. For low idle and rated rpm, see the engine identification plate. If air pressure falls below minimum pressure, the braking ability of the vehicle will be limited. Slow the vehicle down and bring it to a gradual stop. Do not attempt to move the vehicle until air pres- sure has risen above the minimum level. Moving a vehicle without adequate braking power could cause an accident resulting in property damage, personal injury, or death. Voltmeter The voltmeter (see Fig.
3.7 ) indicates the vehicle charging system voltage when the engine is running 3.5