Specifications

Data Parameters Engine Parameters

engines have an airflow sensor to measure the mass, or weight, of air entering the engine. The

airflow sensor delivers a signal that indicates the mass airflow in milligrams per second at any

given instant. The ECU uses the signal from the airflow sensor and other sensors to determine

the air-fuel ratio needed by the engine and the amount of fuel to be injected.

NOMINAL ENGINE SPEED

Range: ____________________________________________________0 to engine max

Used on ARA/ELR, ERE/EVE/ASF (IFI Diesel)), HMF, ME10, and ME20 systems. This

parameter displays the desired engine speed that the ECU is trying to maintain. If there is a large

difference between actual speed and desired RPM readings, the ECU may have reached its

control limit, and can no longer control engine speed. This may be due to a basic mechanical or

electrical problem with the engine.

NOMINAL FUEL RACK TRAVEL

NOMINAL INJ. TIM. ADV. TRAVEL

NOMINAL MANIFOLD ABSOL. PRESS.

NOMINAL PRESSURE DISTRIB. PIPE

NOMINAL SLIDE VALVE ACTUATOR

NOMINAL START OF INJECTION

Range: _______________________________________ variable mm, mbar, or degrees

NOMINAL VEHICLE SPEED

Range: ___________________________________________________ 0 to vehicle max

OPERATING ACTUAL RPM

OPERATING NOMINAL RPM

Range: ____________________________________________________0 to engine max

Used on ERE/EVE/ASF (IFI Diesel)) systems. These parameters are the measurements that the

ECU is trying to maintain. If there is a large difference between actual measurements and

desired readings, the ECU may have reached its control limit without being able to control the

engine. This may be due to a basic mechanical or electrical problem with the engine.

NUMBER OF STARTS WITH NON-LOCKED ECM

Range: ____________________________________________________________1 to 25

Used on ME10 and ME20 systems. This parameter displays the number of engine starts since

ECU installation. A program coding option can be configured to lock or not lock the ECU to the

vehicle it is installed in. This feature locks or codes the ECU to a specific vehicle after a certain

number of engine starts (up to 25). This prevents this ECU from being used on another vehicle. A

locked ECU must be sent to Mercedes-Benz to be uncoded from a specific vehicle.

O2 CONTROL DOWNSTREAM CAT, CYL 1-3;4-6;7-9;10-12

O2 CONTROL UPSTREAM CAT, CYL 1-3;4-6;7-9;10-12

O2 CONTROL, DOWNSTREAM CAT, LEFT

O2 CONTROL, DOWNSTREAM CAT, RIGHT

O2 CONTROL, UPSTREAM CAT, LEFT

O2 CONTROL, UPSTREAM CAT, RIGHT

Range: __________________________________________________________ ON/OFF

Used on ME27 and ME28 systems. These parameters display the state of the downstream and

upstream oxygen sensors (O2S) and circuits for each bank or groups of cylinders. The terms

“1-3,” “4-6,” “7-9,” and “10-12” refer to four separate groups of parameters. ON indicates that the

ECU is using a particular O2S and its circuit.