Electronic Control System; Introduction To The Electronic Control System - Mitsubishi Eclipse Technical Information Manual

Electronic Control System

INTRODUCTION TO THE ELECTRONIC CONTROL SYSTEM

The advantage of using the electronic control system
is more precise control over transaxle function. An
added advantage of the system is that it can help
the technician find a problem in a malfunctioning
transaxle. The system can do this through what
is called On-Board Diagnostics. The Transmission
Control Module (TCM) continuously monitors its criti-
cal functions during normal operation. It records
malfunctions in the form of diagnostic trouble codes
and the number of engine starts since the last code
stored in memory. The technician can use this in-
formation in the event of a malfunction or complaint.
Up to seven, two digit numeric diagnostic trouble
codes may be stored in memory at one time.
When a failure is identified by the TCM, the system
may go into a limp-in mode by turning off the sole-
noids. TCM logic is included to ensure that the limp-
in event results in an orderly shut-down of transaxle
Electronic Control System
Each of the major system components are repre-
sented as a block of information. The lines between
the blocks represent the flow of input and output
information between the components.
Some of the input and output information is unique
to the TCM. In other words, some of the input to
the TCM is "Direct Input." Some information (input)
to the TCM is shared with other components through
POWER TRAIN - Automatic Transaxle
function when possible. The shut-down sequence
will vary depending on which gear the transaxle
is in and what the vehicle speed is at the time the
failure is identified by the TCM. This "all-solenoids
off" limp-in mode is designed to allow for shift lever
manual control of PARK, REVERSE, NEUTRAL and
SECOND GEAR operation. When any forward gear
shift lever position is chosen, the transaxle will re-
main in second gear range.
All failures do not result in limp-in, just those that
could potentially cause internal transaxle damage.
If the TCM itself fails, the transaxle will also go
into the limp-in mode.
The transaxle control system consists of an electron-
ic control module, called the TCM, and a system
of input and output components, that function togeth-
er to control the operation of the transaxle.
the Chrysler Collision Detection (CCD) data bus.
As the TCM receives input information, it continuous-
ly processes it through its logic circuits in order
to perform all of the control functions that it has
been designed to perform. The following is a list
of inputs related to the transaxle control system,
both direct and indirect.