Specifications

70
Data Parameters Engine Parameters
50% duty cycle is the base point, so a 50% reading indicates no ECU fuel correction. Readings
above 50% indicate the ECU is correcting a lean condition, readings below 50% indicate the
ECU is reducing fuel.
OUTPUT DEMAND DUTY CYCLE
Range: _________________________________________________________ 0 to 100%
Used on ME20 systems. This parameter displays the duty cycle of the ECU output to the engine
cooling fan. The display is only active when the fan is operating. Readings vary with fan speed
and cooling demand.
OUTPUT DEMAND DUTY CYCLE(%)
Range: ________________________________________________________ 0 to +100%
Used on ME20 systems. This parameter displays the duty cycle of the ECU output to the engine
cooling fan. The display is only active when the fan is operating, readings vary with fan speed
and cooling demand.
OUTPUT SHAFT SPEED
Range: ____________________________________________________0 to engine max
Used on EAG and EGS systems. This parameter is the engine output shaft speed in RPM.
OXYGEN SENSOR (O2S)
Range: __________________________________________________________ YES/NO
Used on DM systems. Indicates whether the oxygen sensor (O2S) is active or not.
P/N RECOGNIZED
Range: __________________________________________________________ YES/NO
Used on HFM systems. This parameter displays the status of the Park/Neutral position (PNP)
switch signal to ECU. The display should read YES (OK to engage starter) when the selector
lever is in the park or neutral position, and NO when the selector is in any other range.
PARKING BRAKE
Range: __________________________________________________________ ON/OFF
Used on ERE/EVE/ASF (IFI Diesel)) systems. This parameter indicates whether the parking
(hand) brake is on or off.
PART LOAD FUEL TRIM ADAPTAT. LEFT
PART LOAD FUEL TRIM ADAPTAT. RIGHT
Range: __________________________________________________________ variable
Used on ME27 and ME28 systems. These fuel trim numbers represent the long term correction
to the fuel injection pulse width when the engine is under partial load. This number is learned by
the ECU and is used to correct small differences between engines and engine wear. When the
short term correction (O2 Integrator) is outside the window defined in the ECU memory, the long
term fuel trim is changed. PART LOAD FUEL TRIM can modify injector duration using a self-
adaptation factor. A 1.0 reading represents the base point. Readings greater than 1.0 indicate
that the system is lean, and to correct, the duration of injection is increased. Readings less than
1.0 indicate that the system is rich, and to correct, the duration of injection is decreased. This
correction factor affects only those adaptive learn memory cells controlling long term fuel
correction in the part-load operation (lower to mid-range). This type of fuel trim adaptation is also
called multiplicative because the change to injector duration is proportional to the base injector
duration. This adaptation addresses faults that increase with engine speed, such as faulty
injectors. In this case, the amount of adaptation needs to multiply injector pulse in proportion to
the speed increase.
The actual fuel mixture adjustment in each cell depends on the pre-programmed base pulse
width, base injection duration, original fuel, and RPM/Load mapping with no correction. On ME28