TROUBLE DIAGNOSIS — INTRODUCTION
AT-57
[EURO-OBD]
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TROUBLE DIAGNOSIS — INTRODUCTIONPFP:00000
IntroductionECS004QO
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 EURO-OBD related parts
of the A/T system for malfunction-diagnostic purposes. The TCM is
capable of diagnosing malfunctioning parts while the ECM can store
malfunctions 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- 6 1 , "
Work Flow" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a drive ability 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” like the exam-
ple (AT- 5 8 , "
DIAGNOSTIC WORKSHEET" ) should be used.
Start your diagnosis by looking for “conventional” problems first. This
will help troubleshoot drive ability problems on an electronically con-
trolled engine vehicle.
Also check related Service bulletins for information.
SAT631IA
SAT632I
SEF234G
AT-68
[EURO-OBD]
TROUBLE DIAGNOSIS — BASIC INSPECTION
Line Pressure TestECS004QS
LINE PRESSURE TEST PORTS
Location of line pressure test ports are shown in the illustration.
Always replace pressure plugs as they are self-sealing
bolts.
LINE PRESSURE TEST PROCEDURE
1. Check A/T fluid and engine oil levels. If necessary, add fluid or
oil.
2. Drive vehicle for approx. 10 minutes or until engine oil and ATF
reach operating temperature. Refer to AT- 1 6 , "
Checking A/T
Fluid" .
3. Install pressure gauge to corresponding line pressure port.
4. Set parking brake and block wheels.
Continue to depress brake pedal fully while line pressure
test is being performed at stall speed.
SCIA0709E
SAT647B
UAT008
SAT513G
AT-96
[EURO-OBD]
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
*1: These terminals are connected to the ECM.
*2: These terminals are connected to the data link connector.34 W/GPNP switch “D”
position
and When setting selector lever to “D”
position.Battery voltage
When setting selector lever to other
positions.0V
35 Y/GPNP switch “R”
positionWhen setting selector lever to “R”
position.Battery voltage
When setting selector lever to other
positions.0V
36 GPNP switch “P”,
“N” positionWhen setting selector lever to “P”,
“N” position.Battery voltage
When setting selector lever to other
positions.0V
39 *1 L/OREngine speed sig-
nal
and Refer to EC-95
.—
40 L/BVehicle speed
sensorWhen moving vehicle at 2 to 3 km/h
(1 to 2 MPH) for 1 m (3 ft) or more.Voltage varies
between less
than 0V and
more than 4.5V
41 G/YAccelerator pedal
position (APP)
sensorWhen depressing accelerator pedal
slowly after warming up engine.
(Voltage rises gradually in response
to throttle position.)Fully-closed
throttle: 0.5V
Fully-open throt-
tle: 4V
42 B Sensor ground Always 0V
47 BRA/T fluid tempera-
ture sensorWhen ATF temperature is 20°C
(68°F).1.5V
When ATF temperature is 80°C
(176°F).0.5V
48 B Ground Always 0V Te r m i -
nal No.Wire color Item ConditionJudgementstan-
dard(Approx.)
AT-148
[EURO-OBD]
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVEPFP:31940
DescriptionECS004RQ
The torque converter clutch solenoid valve is activated, with the gear
in “D
4 ”, by the TCM in response to signals sent from the vehicle
speed and throttle position sensors. Lock-up piston operation will
then be controlled.
Lock-up operation, however, is prohibited when A/T fluid tempera-
ture is too low.
When the accelerator pedal is depressed (less than 2/8) in lock-up
condition, the engine speed should not change abruptly. If there is a
big jump in engine speed, there is no lock-up.
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
On Board Diagnosis LogicECS00CU4
Possible CauseECS00CU5
Check the following items.
Torque converter clutch solenoid valve
Harness or connector
(The solenoid circuit is open or shorted.)
DTC Confirmation ProcedureECS00CU6
CAUTION:
Always drive vehicle at a safe speed.
If performing this “DTC Confirmation Procedure” again, always turn ignition switch OFF and wait
at least 10 seconds before continuing.
NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch OFF and
wait at least 5 seconds before conducting the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch ON. (Do not start engine.)
2. Select “DATA MONITOR” mode for “A/T” with CONSULT-II and
wait at least 1 second.
3. Start engine and maintain the following conditions for at least 5
consecutive seconds.
VHCL SPEED SE: 80 km/h (50 MPH) or more
THROTTLE POSI: 0.5/8 - 1.0/8
Selector lever: D position (O/D ON)
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
4. If the check result is NG go to AT- 1 5 1 , "
Diagnostic Procedure" .
SCIA0718E
Monitor item Condition Specification
Torque converter clutch solenoid valve
dutyLock-up OFF
↓
Lock-up ONApproximately 4%
↓
Approximately 94%
Diagnostic trouble code Malfunction is detected when... Check items (Possible cause)
: T/C CLUTCH SOL/V
TCM detects an improper voltage drop
when it tries to operate the solenoid valve.
Harness or connectors
(The solenoid circuit is open or shorted.)
T/C clutch solenoid valve
: P0740
SAT014K
AT-154
[EURO-OBD]
DTC P0745 LINE PRESSURE SOLENOID VALVE
DTC P0745 LINE PRESSURE SOLENOID VALVEPFP:31940
DescriptionECS004RU
The line pressure solenoid valve regulates the oil pump discharge
pressure to suit the driving condition in response to a signal sent
from the TCM.
The line pressure duty cycle value is not consistent when the
closed throttle position switch is ON. To confirm the line pres-
sure duty cycle at low pressure, the accelerator (throttle)
should be open until the closed throttle position switch is OFF.
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
NOTE:
The line pressure duty cycle value is not consistent when the closed throttle position switch is “ON”. To confirm the line pressure duty
cycle at low pressure, the accelerator (throttle) should be open until the closed throttle position switch is “OFF”.
On Board Diagnosis LogicECS00CU7
Possible CauseECS00CU8
Check the following items.
Harness or connector
(The solenoid circuit is open shorted.)
Line pressure solenoid valve
DTC Confirmation ProcedureECS00CU9
NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch OFF and
wait at least 5 seconds before conducting the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode for
“A/T” with CONSULT-II.
SCIA0735E
Monitor item Condition Specification
Line pressure solenoid valve dutySmall throttle opening
(Low line pressure)
↓
Large throttle opening
(High line pressure)Approximately 0%
↓
Approximately 95%
Diagnostic trouble code Malfunction is detected when... Check items (Possible cause)
: LINE PRESSURE S/V
TCM detects an improper voltage drop
when it tries to operate the solenoid valve.
Harness or connectors
(The solenoid circuit is open or shorted.)
Line pressure solenoid valve
: P0745
SAT014K
DTC P0750 SHIFT SOLENOID VALVE A
AT-161
[EURO-OBD]
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DTC P0750 SHIFT SOLENOID VALVE APFP:31940
DescriptionECS004RY
Shift solenoid valves A and B are turned ON or OFF by the TCM in
response to signals sent from the PNP switch, vehicle speed and
throttle position sensors. Gears will then be shifted to the optimum
position.
CONSULT-II REFERENCE VALUE IN DATE MONITOR MODE
Remarks: Specification data are reference values.
On Board Diagnosis LogicECS00CUA
Possible CauseECS00CUB
Check the following items.
Harness or connector
(The solenoid circuit is open or shorted.)
Shift solenoid valve A
DTC Confirmation ProcedureECS00CUC
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch OFF and
wait at least 5 seconds before conducting the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
SCIA0718E
Gear position 1 2 3 4
Shift solenoid valve A ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed) ON (Closed) OFF (Open) OFF (Open)
Monitor item Condition Display value
SHIFT S/V A (ON/OFF)When shift solenoid valve A operates.
(When driving in D
1 or D4 .)ON
When shift solenoid valve A does not operate.
(When driving in D
2 or D3 .)OFF
Diagnostic trouble code Malfunction is detected when... Check items (Possible cause)
: SHIFT SOLENOID/V A
TCM detects an improper voltage drop
when it tries to operate the solenoid valve.
Harness or connectors
(The solenoid circuit is open or shorted.)
Shift solenoid valve A
: P0750
DTC P0755 SHIFT SOLENOID VALVE B
AT-167
[EURO-OBD]
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DTC P0755 SHIFT SOLENOID VALVE BPFP:31940
DescriptionECS004S2
Shift solenoid valves A and B are turned ON or OFF by the TCM in
response to signals sent from the PNP switch, vehicle speed and
throttle position sensors. Gears will then be shifted to the optimum
position.
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
On Board Diagnosis LogicECS00CUD
Possible CauseECS00CUE
Check the following items.
Harness or connector
(The solenoid circuit is open or shorted.)
Shift solenoid valve B
DTC Confirmation ProcedureECS00CUF
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch OFF and
wait at least 5 seconds before conducting the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
SCIA0718E
Gear position 1 2 3 4
Shift solenoid valve A ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed) ON (Closed) OFF (Open) OFF (Open)
Monitor item Condition Display value
SHIFT S/V B (ON/OFF)When shift solenoid valve B operates.
(When driving in D
1 or D2 .)ON
When shift solenoid valve B does not operate.
(When driving in D
3 or D4 .)OFF
Diagnostic trouble code Malfunction is detected when... Check items (Possible cause)
: SHIFT SOLENOID/V B
TCM detects an improper voltage drop
when it tries to operate the solenoid valve.
Harness or connectors
(The solenoid circuit is open or shorted.)
Shift solenoid valve B
: P0755
AT-176
[EURO-OBD]
DTC P1705 ACCELERATOR PEDAL POSITION (APP) SENSOR
TERMINALS AND REFERENCE VALUE MEASURED BETWEEN EACH TERMINAL
Diagnostic ProcedureECS004S8
1. CHECK DTC WITH ECM
Perform diagnostic test mode II (self-diagnostic results) for engine control.
Refer to EC-64, "
Malfunction Indicator (MI)" .
OK or NG
OK (With CONSULT-II)>>GO TO 2.
OK (Without CONSULT-II)>>GO TO 3.
NG >> Check throttle position sensor circuit for engine control.
Te r m i -
nal No.Wire color Item ConditionJudgement standard
(Approx.)
32 RAccelerator pedal
position (APP)
sensor
(Power source)orWhen turning ignition switch ON 4.5 - 5.5V
When turning ignition switch OFF 0V
41 G/YAccelerator pedal
position (APP)
sensorWhen depressing accelerator pedal
slowly after warming up engine.
(Voltage rises gradually in response
to throttle position.)Fully-closed throttle:
0.5V
Fully-open throttle:
4V
42 B Sensor ground Always 0V