Battery power is low.
Battery has been disconnected for a long time.
Battery is connected conversely.
(When reconnecting TCM connectors. — This is not a problem.)

Lamp comes on.

PNP switch, overdrive control switch or throttle position switch cir-
cuit is disconnected or TCM is damaged.
Þ Go to

AT-387, "21. TCM Self-diagnosis Does Not Activate

(PNP, Overdrive Control and Throttle Position Switches Cir-
cuit Checks)"

O/D OFF indicator lamp:

SAT455F

SAT457F

SAT367J

O/D OFF indicator lamp:

All judgement flickers are same.

All circuits that can be confirmed by self-diagnosis are OK.

1st judgement flicker is longer than others.

Revolution sensor circuit is short-circuited or disconnected.
Þ Go to

AT-261, "DTC P0720 VEHICLE SPEED SENSOR·A/T

(REVOLUTION SENSOR)"

2nd judgement flicker is longer than others.

Vehicle speed sensor circuit is short-circuited or disconnected.
Þ Go to

AT-340, "DTC VEHICLE SPEED SENSOR·MTR"

3rd judgement flicker is longer than others.

Throttle position sensor circuit is short-circuited or disconnected.
Þ Go to

AT-321, "DTC P1705 THROTTLE POSITION SEN-

SOR"

LAT425

LAT426

LAT427

LAT428

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION

AT-203

[RE4R01A]

= 2.5 seconds

= 2.0 seconds

= 1.0 second

4th judgement flicker is longer than others.

Shift solenoid valve A circuit is short-circuited or disconnected.
Þ Go to

AT-311, "DTC P0750 SHIFT SOLENOID VALVE A"

5th judgement flicker is longer than others.

Shift solenoid valve B circuit is short-circuited or disconnected.
Þ Go to

AT-316, "DTC P0755 SHIFT SOLENOID VALVE B"

6th judgement flicker is longer than others.

Overrun clutch solenoid valve circuit is short-circuited or discon-
nected.
Þ Go to

AT-329, "DTC P1760 OVERRUN CLUTCH SOLENOID

VALVE"

7th judgement flicker is longer than others.

Torque converter clutch solenoid valve circuit is short-circuited or
disconnected.
Þ Go to

AT-293, "DTC P0740 TORQUE CONVERTER CLUTCH

SOLENOID VALVE"

8th judgement flicker is longer than others.

A/T fluid temperature sensor is disconnected or TCM power
source circuit is damaged.
Þ Go to

AT-334, "DTC BATT/FLUID TEMP SEN (A/T FLUID

TEMP SENSOR CIRCUIT AND TCM POWER SOURCE)"

9th judgement flicker is longer than others.

Engine speed signal circuit is short-circuited or disconnected.
Þ Go to

AT-266, "DTC P0725 ENGINE SPEED SIGNAL"

10th judgement flicker is longer than others.

Þ Go to

AT-344, "DTC TURBINE REVOLUTION SENSOR

(VG33ER ONLY)"

11th judgement flicker is longer than others.

Line pressure solenoid valve circuit is short-circuited or discon-
nected.
Þ Go to

AT-306, "DTC P0745 LINE PRESSURE SOLENOID

VALVE"

Flickers as shown below.

Battery power is low.
Battery has been disconnected for a long time.
Battery is connected conversely.
(When reconnecting TCM connectors. — This is not a problem.)

Lamp comes on.

PNP switch, overdrive control switch or throttle position switch cir-
cuit is disconnected or TCM is damaged.
Þ Go to

AT-387, "21. TCM Self-diagnosis Does Not Activate

(PNP, Overdrive Control and Throttle Position Switches Cir-
cuit Checks)"

O/D OFF indicator lamp:

LAT429

LAT430

LAT431

LAT432

LAT433

LAT434

LAT435

SAT455F

SAT457F

SAT367J

AT-204

[RE4R01A]

TROUBLE DIAGNOSIS — INTRODUCTION

PFP:00000

Introduction

ECS007LU

The TCM receives a signal from the vehicle speed sensor, throttle
position sensor or PNP switch and provides shift control or lock-up
control via A/T solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used with the OBD-related parts of the
A/T system for malfunction-diagnostic purposes. The TCM is capa-
ble of diagnosing malfunctioning parts while the ECM can store mal-
functions in its memory.
Input and output signals must always be correct and stable in the
operation of the A/T system. The A/T system must be in good oper-
ating condition and be free of valve seizure, solenoid valve malfunc-
tion, etc.
It is much more difficult to diagnose a problem that occurs intermit-
tently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the problems. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow the “Work Flow”. Refer to

AT-208, "Work Flow"

.
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such problems, especially
intermittent ones. Find out what symptoms are present and under what conditions they occur. A “Diagnostic
Worksheet” should be used. Refer to

AT-205, "DIAGNOSTIC WORKSHEET"

Start your diagnosis by looking for “conventional” problems first. This
will help troubleshoot driveability problems on an electronically con-
trolled engine vehicle.
Also check related Service bulletins.

AAT473A

SAT632I

SEF234G

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