System Description; Basic Troubleshooting - Toyota MR2 1988 Repair Manual

AT-2
AUTOMATIC TRANSAXLE - System Description, Troubleshooting
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SYSTEM DESCRIPTION
The transaxle for A240E and A241 E, also called Electronic
Controlled Transaxle (ECT), differs from the oil pressure control
type transaxle in that it is controlled by a microcomputer.
Accordingly, troubleshooting procedurE!S differ also.
Trouble occurring in the ECT can
stE~m
from one of three
sources: the engine, the ECT electronic control unit or the
transaxle itself. Before troubleshooting, determine in which of
these three sources the problem lies, and begin troubleshooting
with the simplest operation, gradually working up in order of
difficulty.
TROUBLESHOOTING
Basic Troubleshooting
Before troubleshooting an ECT, first determine whether the
problem is electrical or mechanical. To do this, just refer to the
basic troubleshooting flow-chart provided below.
If the cause is already known, using the basic troubleshooting
chart below along with the general troubleshooting chart on the
following page should speed the procedure.
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Preliminary Check
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Bad
(See page AT -5)
OK
Read Diagnostic Code
(See pages AT-23)
OK
Manual Shifting Test
(See page AT- 7)
OK
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Bad
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Bad
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Repair or
Replace
I Electrical Control System Check
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Stall Test, Time Lag Test, and
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Hydraulic Test
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Repair or Replace I
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Repair Transmission