Electronic Controls
Electronic Control Module
The engine uses two Electronic Control Modules for normal engine operation. The Primary ECM and the Secondary ECM control the engine. The modules communicate over a data link. If the Primary ECM fails the Secondary ECM will take over control of the fuel injectors. Engine monitoring from the Primary ECM will be lost until the ECM recovers.
The ECM supplies signals to the Electronic Fuel Injectors. The ECM signals control the engine operation. The ECM consists of two main components, the control computer (hardware) and the Personality Module (software). The control computer consists of a microprocessor and electronic circuitry. The Personality Module is the software for the control computer which contains operating maps that define power and torque curves.
The ECM governs engine speed. Actual engine rpm is determined by the Engine Speed/Timing signal. The primary ECM is located on the front left of the engine. The secondary ECM is located on the right side of the engine. There are two speed sensors. The primary speed sensor and the secondary speed sensor are located in the engine timing gear housing. The primary ECM and the secondary ECM are capable of functioning with either the primary speed sensor or the secondary speed sensor.
Fuel Injection
The ECM controls the timing of the fuel injectors. The ECM varies the signals to the fuel injectors. Fuel is injected ONLY while an injector solenoid is energized by a 105 volt signal from the ECM. By controlling the timing and duration of the 105 volt signal, the ECM controls the fuel injection timing, the quantity of fuel and the desired engine rpm. The range of the signal to the injector solenoids is 105 + 1, - 15 volts.
Injection timing depends on the engine rpm, load, and other operational factors. The ECM detects the top center of each cylinder. The ECM sends an injection signal at the desired time. The ECM limits engine power during cold mode operation.
The ECM modifies the injection timing and the ECM cuts out the cylinders. This will increase startability and this will reduce warm up time. Cold Mode is activated whenever the engine coolant temperature falls below a predetermined value.
Cold Mode remains active until the engine has warmed or a time limit is exceeded. The ECM is programmed at the factory which limits the quantity of fuel that can be injected.
The Rated Fuel Position is a limit that is based on the engine power rating. This is similar to the rack stops and the torque spring on a mechanically governed engine. The Rated Fuel Position provides power. The Rated Fuel Position provides the power curves and the torque curves for a specific engine family.
Note: The front end of the engine is opposite the flywheel end of the engine. The left side and the right side of the engine are determined from the flywheel end. The number 1 cylinder is the front cylinder on the right side. The number 2 cylinder is the front cylinder on the left side.
Engine Wiring Diagram for the 3512B Engine
 | |
| Illustration 1 | g00923805 |
Primary ECM | |
Engine Wiring Diagram for the 3512B Engine
 | |
| Illustration 2 | g00923827 |
Secondary ECM | |
Location Of The Engine Sensors
 | |
| Illustration 3 | g00874433 |
Left side view (1) Engine crankcase pressure sensor (2) Versatile Control Module (VCM) (3) Engine speed-timing sensor (secondary) (4) Engine speed-timing sensor (primary) (5) DFW generator lube oil cooler outlet temperature sensor (6) DLO generator pump discharge pressure sensor (7) DLO generator cooler inlet temperature sensor (8) DLO generator cooler outlet temperature sensor (9) DFW generator lube oil cooler inlet temperature sensor | |
Location Of The Engine Sensors
 | |
| Illustration 4 | g00842896 |
Front view (10) DFW engine outlet temperature sensor (11) DLO engine oil filter inlet pressure sensor (12) DLO engine oil filter outlet pressure sensor (13) DO engine filter inlet pressure sensor (14) DO engine filter outlet pressure sensor (15) Compartment pressure sensor (16) Engine air manifold pressure sensor (17) Primary ECM | |
Location Of The Engine Sensors
 | |
| Illustration 5 | g00874403 |
Right side view (18) DFW aftercooler outlet temperature sensor (19) Integrated Temperature Sensing Module (ITSM) (20) Secondary ECM (21) DLO engine pump discharge pressure sensor (22) DFW pump outlet temperature sensor (23) DFW pump discharge pressure sensor (24) DLO engine lube oil cooler inlet temperature sensor (25) DFW engine lube oil cooler outlet temperature sensor | |
Location Of The Engine Sensors
 | |
| Illustration 6 | g00923840 |
Top view (26) Engine air manifold outlet temperature sensor (27) Turbocharger outlet temperature (right) (28) Exhaust manifold temperature sensor (right) (29) Air filter sensor (right) (30) DLO to generator bearing pressure sensor (31) Air filter sensor (left) (32) Exhaust manifold temperature sensor (left) (33) Turbocharger outlet temperature (left) (34) cylinder head temperature sensor (1 per cylinder) (35) DLO engine inlet temperature sensor | |