Mitsubishi L200. Manual - part 281

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-31

NOTE: 

*

: When the diagnosis code related to the 

CAN communication error is set, check the vehicle 
equipment. If this system is not equipped, the diag-
nosis code is always set, but it is not abnormal.

P1779

−

1st gear ratio does not meet the specification

P.23A-64

 

<4A/T>

P.23A-65

 

<5A/T>

P1780

−

2nd gear ratio does not meet the specification

P1781

−

3rd gear ratio does not meet the specification

P1782

−

4th gear ratio does not meet the specification

P1783

−

5th gear incorrect ratio <5A/T>

P1784

−

Reverse gear ratio does not meet the specification

P1786

−

DCC solenoid valve system

P.23A-67

P1787

−

P.23A-68

P1788

P1751

A/T control relay system

P.23A-69

P1790

−

Back up line system

P.23A-73

P1901

−

Can signal time-out (Engine-ECU)

P.23A-74

U1073

−

Bus Off

P.23A-75

U1100

*

−

Engine-ECU time-out (related to engine)

P.23A-76

U1102

*

−

ASTC-ECU time-out

P.23A-77

U1109

*

−

ETACS-ECU time-out

P.23A-78

U1120

*

−

Failure information of Engine-ECU

P.23A-79

U1190

*

−

Can’t receive fault detection control signal

P.23A-80

Diagnosis code No.

Diagnosis item

Reference 
page

M.U.T.-III

General 
scan tool

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-32

DIAGNOSIS CODE PROCEDURES

Code No.P1763 (P0710) A/T fluid temperature sensor system

A/T-ECU

A/T CONTROL
SOLENOID
VALVE ASSEMBLY

A/T
FLUID
TEMPERATURE
SENSOR

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet     PU : Purple

A/T Fluid Temperature Sensor System Circuit

AC903903

AC510056AD

Harness side

B-10 (B)

Connector: B-10

AC510056AC

Harness side

B-11 (B)

Connector: B-11

AC510056AB

Harness side

B-15 (B)

Connector: B-15

AC510057

Harness side

A/T-ECU

C-12

AB

Connector: C-12

A/T-ECU

<RHD>

<LHD>

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-33

OPERATION

• The A/T fluid temperature sensor converts the A/

T fluid temperature to voltage, and send the infor-
mation to the A/T-ECU.

• The A/T fluid temperature rises, the resistance 

decreases. Thus, the sensor output voltage 
depends on the A/T fluid temperature. As the A/T 
fluid temperature rises, the output voltage will 
decrease.

DIAGNOSIS CODE SET CONDITIONS
If the A/T fluid temperature sensor output voltage is 
4.5 volts or more after driving for 10 minutes or more, 
there is an open circuit in the A/T fluid temperature 
sensor and diagnosis code No.P1763 (P0710) is set.

PROBABLE CAUSES

• Malfunction of the A/T fluid temperature sensor

• Damaged harness wires and connectors

• Malfunction of the A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list
Item 07: A/T fluid temperature sensor (Refer to Data 
List Table 

P.23A-103

). 

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Go to Step 2.

STEP 2. Measure the resistance at A/T control 
solenoid valve assembly connector B-15.
Disconnect the connector, and measure the resist-
ance between terminal 1 and 2 at the sensor side.

OK: 

• 16.7 − 20.5 kΩ (at 0°C)

• 7.3 − 8.9 kΩ (at 20°C)

• 3.4 − 4.2 kΩ (at 40°C)

• 1.9 − 2.2 kΩ (at 60°C)

• 1.0 − 1.2 kΩ (at 80°C)

• 0.57 − 0.69 kΩ (at 100°C)

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the A/T fluid temperature sensor.

STEP 3. Connector check: B-15 A/T control 
solenoid valve assembly
Check for the contact with terminals.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the defective connector.

STEP 4. Measure the resistance at A/T control 
solenoid valve assembly connector B-15.
Disconnect the connector, and measure the resist-
ance between terminal 2 and earth at the wiring har-
ness side.

OK: Continuity (Less than 2 

Ω)

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Go to Step 5.

STEP 5. Measure the voltage at A/T-ECU 
connector C-12.
(1) Connect A/T control solenoid valve assembly 

connector B-15.

(2) Turn the ignition switch to the ON position.
(3) Measure the voltage between A/T-ECU 

connector C-12 terminal No.43 and earth. 

OK: 0.5 V or less

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Go to Step 6.

STEP 6. Connector check: C-12 A/T-ECU 
connector
Check for the contact with terminals.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the defective connector.

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-34

STEP 7. M.U.T.-III data list
Item 07: A/T fluid temperature sensor (Refer to Data 
List Table 

P.23A-103

.) 

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Replace the A/T-ECU.

STEP 8. Connector check: B-11 intermediate 
connector, C-12 A/T-ECU connector
Check for the contact with terminals.

Q: Is the check result normal?

YES : 

Go to Step 14.

NO : 

Repair the defective connector.

STEP 9. Measure the voltage at A/T control 
solenoid valve assembly connector B-15.
(1) Disconnect the connector, and measure the 

voltage between terminal 1 and earth at the 
wiring harness side.

(2) Turn the ignition switch to the ON position.

OK: 4.5 

− 4.9 V

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 10.

STEP 10. Measure the voltage at A/T-ECU 
connector C-12.
(1) Connect A/T control solenoid valve assembly 

connector B-15.

(2) Turn the ignition switch to the ON position.
(3) Measure the voltage between A/T-ECU 

connector C-12 terminal No.44 and earth. 

OK: 

• 3.8 − 4.0 V (at 20°C)

• 3.2 − 3.4 V (at 40°C)

• 1.7 − 1.9 V (at 80°C)

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Go to Step 11.

STEP 11. Connector check: C-12 A/T-ECU 
connector
Check for the contact with terminals.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the defective connector.

STEP 12. Connector check: B-10 intermediate 
connector, C-12 A/T-ECU connector
Check for the contact with terminals.

Q: Is the check result normal?

YES : 

Go to Step 13.

NO : 

Repair the defective connector.

STEP 13. Check the harness between A/T control 
solenoid valve assembly connector B-15 terminal 
No.1 and A/T-ECU connector C-12 terminal No.44.
Check the output line for short-circuited or open cir-
cuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

STEP 14. Check the harness between A/T control 
solenoid valve assembly connector B-15 terminal 
No.2 and A/T-ECU connector C-12 terminal No.43.
Check the earth line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

Code No.P1764 (P0710) A/T fluid temperature sensor system

A/T FLUID TEMPERATURE SENSOR SYSTEM 
CIRCUIT
 Refer to 

P.23A-32

.

OPERATION
 Refer to 

P.23A-32

.

DIAGNOSIS CODE SET CONDITION
If the A/T fluid temperature sensor output voltage has 
been approximately 0 V for at least one second (indi-
cating abnormally high oil temperature), it indicates 
that the A/T fluid temperature sensor circuit is 
shorted and diagnosis code No.1764 (P0710) is set.