THEORY OF OPERATION - CONTINUED
TRANSMISSION - CONTINUED
Transmission oil temperature sensor monitors temperature of transmission oil. Transmission oil tempera-
ture sensor is mounted below transmission relief valve.
Torque converter temperature sensor monitors temperature of torque converter oil. Torque converter tem-
perature sensor is mounted on top of transmission on torque converter housing.
Brake Oil Pressure Sensor. Transmission neutralizer function consists of a brake pressure sensor mounted on brake
valve. When brakes are applied, pressure sensor sends a signal to machine ECM. Machine ECM will neutralize
transmission at proper brake pressure. Machine ECM will engage transmission when brakes are released.
Other Inputs. Machine ECM also receives information from diagnostic connector via CAT data link, engine ECM
via CAN data link, and instrument cluster.
Electronic Control Module (Machine). Machine ECM makes decisions for transmission operation based on informa-
tion from inputs and memory. Machine ECM controls many machine functions:
Powertrain is electronically controlled by
machine ECM (which is why, machine ECM can
be referred to as powertrain ECM).
Although some engine-related functions are con-
trolled by machine ECM, engine has an ECM
that controls most engine functions.
After machine ECM receives information from
inputs and memory, it will send a corresponding
response through outputs. Inputs and outputs of
machine ECM connect to machine harness by
two 70-pin connectors (J1 and J2).
Machine has several input devices. Machine ECM receives information from components about machine opera-
tions. Machine has switch-type inputs and sensor-type inputs. Switches provide signals to switch ECM inputs. Pos-
sible outputs of a switch are listed: open signal, grounded signal, +battery signal. Sensors provide a signal to ECM
that constantly changes. Inputs to machine ECM are listed in Tables 1 and 2 for 70-pin connectors.
Machine ECM sends electrical signals through outputs. Outputs can create an action or provide information to
machine ECM. Outputs for machine ECM are listed in Tables 1 and 2. Engine ECM and machine ECM use CAT
data link to communicate with each other. Data link is bidirectional, meaning ECM can receive and send informa-
tion. Data link allows information sharing with other ECMs.
Machine ECM and instrument panel use CAN data link to communicate with each other. Data link is bidirectional,
meaning ECM can receive and send information. Engine information that needs to be displayed on instrument
panel is transmitted to machine ECM on CAT data link. Then, machine ECM sends information to instrument
panel on CAN data link.
A module identifier (MID) is assigned to each ECM. MID for machine ECM is 081.