Specifications

Data Parameters Engine Parameters

FUEL RACK POSITION

Range: __________________________________________________________ variable

Used on EDS diesel systems. The display shows the fuel rack position in millimeters. With the

accelerator not depressed, the display should read approximately 10 mm. The value should

increase to about 20 mm at WOT as the accelerator pedal is slowly depressed.

FUEL TANK CAP

Range: _______________________________________________________ OK/NOT OK

Used on ME10 systems. This parameter indicates whether the fuel tank cap is properly installed.

The display reads OK if the cap is correctly installed. A reading of NOT OK indicates a cap not

sealing, or a major evaporative emissions system leak.

FUEL TANK LEVEL

Range: _______________________________________________________ OK/NOT OK

Used on ME10 and ME20 systems. This parameter indicates whether there is the proper amount

of fuel in the fuel tank to run an evaporative emissions (EVAP) test. The display reads OK if the

fuel level is within test range, and NOT OK if the fuel level is outside the test range.

FUEL TEMPERATURE

Range: __________________________________________ –6 to 116°C or –21 to 240°F

Used on ERE_EVE_ASF (IFI Diesel). Fuel temperature is measured in order to calculate the fuel

density. It is also used for a substitute signal in the event of a coolant temperature sensor failure.

This parameter relies on the fuel temperature sensor, which is located in the electro-hydraulic

fuel cut off valve on the main injection pump. The measurement units can be changed from

degrees Celsius (°C) to degrees Fahrenheit (°F).

FULL LOAD DETECTION

Range: _________________________________________________ ON/OFF or YES/NO

Used on ME27, ME28 and SIM4 systems. This parameter reads YES or ON when the engine

fuel management system is functioning in full load operating mode.

FUNCTION FAULT

Range: __________________________________________________________ YES/NO

Used on HFM systems. This parameter indicates whether a functional problem exists with a

specific component or system. The reading is YES if a fault is detected and NO if not.

HFM VOLTAGE

HOT FILM VOLTAGE

HOT WIRE VOLTAGE

HOT FILM MASS AIR FLOW SENSOR

Range: ________________________________________________________ 0 to 5.00 V

Used on ME10, ME20, ME27, ME28, HFM and LH systems. These parameters show the voltage

required to maintain a 320°F (160 °C) temperature in the heated circuit of the mass air flow

sensor. Normal ranges vary between systems. On ME systems, expect to see 1.4 to 1.5 volts (10

to 20 kilograms per hour (kg/h)) with a hot engine running at idle and all accessories off and 2.0

and 2.2 volts at 3000 RPM. For HFM systems idle readings should be about 0.7 to 0.9 volts and

readings at 3000 RPM about 1.7 to 1.9 volts. With a LH system, look for readings between 0.7

and 1.7 volts at idle. The hot film airflow sensor controls the temperature of the heating resistor

(Rh) with a variable voltage. Temperature is maintained at 320°F (160 °C) above the intake air

temperature detected by the temperature resistor (Rl). The sensor (Rs) monitors heating resistor

(Rh) temperature. If the temperature changes, the ECU alters voltage applied to the heating

resistor (Rh) until the correct temperature difference is again achieved.