SSANGYONG KYRON 2010.01 Manual page 559

01-11
3410-01
2) Processing Logic
Shift schedule and calibration information is stored in an Erasable Programmable Read Only
Memory (EPROM).
Throttle input calibration constants and the diagnostics information are stored in Electrically
Erasable Programmable Read Only Memory (EEPROM) that retains the memory even when
power to the TCU is disconnected.
TCU continuously monitors the input values and uses these, via the shift schedule, to
determine the required gear state. At the same time it monitors, via the solenoid outputs, the
current gear state, whenever the input conditions change such that the required gear state is
different to the current gear state, the TCU initiates a gear shift to bring the two states back into
line.
Once the TCU has determined the type of gearshift required the TCU accesses the shift logic,
estimates the engine torque output, adjusts the variable pressure solenoid ramp pressure then
executes the shift.
The TCU continuously monitors every input and output circuit for short or open circuits and
operating range.
When a failure or abnormal operation is detected the TCU records the condition code in the
diagnostics memory and implements a Limp Home Mode (LHM).
The actual limp home mode used depends upon the failure detected with the object to maintain
maximum driveability without damaging the transmission. In general input failures are handled
by providing a default value.
Output failures, which are capable of damaging the transmission, result in full limp mode giving
only third or fourth gear and reverse. For further details of limp modes and memory retention
refer to the Diagnostic Trouble Code Diagnosis Section.
The TCU is designed to operate at ambient temperatures between - 40 and 85°C (- 40
and 185°F). It is also protected against electrical noise and voltage spikes, however all
the usual precautions should be observed, for example when arc welding or jump starting.
ION 4-SPEED
KYRON 2010.01