Mitsubishi L200. Manual — part 284

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-43

DIAGNOSIS CODE SET CONDITIONS
If the output pulse from the output shaft speed sen-
sor has been lost for one second or more while the
vehicle is being driven, it is judged that there is an
open circuit or short circuit in the output shaft speed
sensor, and diagnosis code No.P1767 (P0720) is
set.
If the code No.P1767 (P0720) is set four times, the
transmission will be fixed in 3rd gear as a fail-safe
measure. However, the transmission can be down-
shifted to 2nd gear by operating the selector lever.

PROBABLE CAUSES

• Malfunction of output shaft speed sensor

• Malfunction of output shaft <4A/T>

• Malfunction of direct planetary carrier <5A/T>

• Damaged harness wires and connectors

• Malfunction of the A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list
Item 06: Output shaft speed sensor (Refer to data list
reference 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. Connector check: B-16 output shaft
speed sensor connector
Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the defective connector.

STEP 3. Measure the resistance at output shaft
speed sensor connector B-16.
Disconnect the connector, and measure the resist-
ance between terminal 1 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 4.

STEP 4. Measure the voltage at A/T-ECU
connector C-12.
(1) Connect output shaft speed sensor connector B-

16.

(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 7.

NO :

Go to Step 5.

STEP 5. Connector check: C-12 A/T-ECU
connector
Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Repair the defective connector.

STEP 6. M.U.T.-III data list
Item 06: Output shaft speed sensor (Refer to data list
reference 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 7. 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 8.

NO :

Repair the defective connector.

STEP 8. Check the harness between output shaft
speed sensor connector B-16 terminal No.1 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 6.

NO :

Repair the wiring harness.

STEP 9. Measure the voltage at output shaft
speed sensor connector B-16.
(1) Disconnect the connector, and measure the

voltage between terminal 3 and earth at the
wiring harness side.

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

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 12.

NO :

Go to Step 10.

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-44

STEP 10. Connectors check: C-208 J/B
connector, B-10 and C-52 <LHD>or C-34 <RHD>
intermediate connector
Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 11.

NO :

Repair the defective connector.

STEP 11. Check the harness between output
shaft speed sensor connector B-16 terminal No.3
and junction block connector C-208 terminal
No.2.
Check the power supply line for short or open circuit.

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Repair the wiring harness.

STEP 12. Measure the voltage at output shaft
speed sensor connector B-16.
(1) Disconnect the connector, and measure the

voltage between terminal 2 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 18.

NO :

Go to Step 13.

STEP 13. Measure the voltage at A/T-ECU
connector C-12.
(1) Disconnect output shaft speed sensor connector

B-16.

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

connector C-12 terminal No.32 and earth.

OK: 4.5

− 4.9 V

Q: Is the check result normal?

YES :

Go to Step 16.

NO :

Go to Step 14.

STEP 14. 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 15.

NO :

Repair the defective connector.

STEP 15. Check the harness between output
shaft speed sensor connector B-16 terminal No.2
and A/T-ECU connector C-12 terminal No.32.
Check the output line for short circuit.

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Repair the wiring harness.

STEP 16. 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 17.

NO :

Repair the defective connector.

STEP 17. Check the harness between output
shaft speed sensor connector B-16 terminal No.2
and A/T-ECU connector C-12 terminal No.32.
Check the output line for open circuit.

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Repair the wiring harness.

STEP 18. Measure the output wave pattern of the
output shaft speed sensor at A/T-ECU connector
C-12 (using an oscilloscope).
(1) Shift the selector lever to the D range.
(2) Accelerate the vehicle to approximately 50 km/h

(shift range; 3rd.)

(3) Connect an oscilloscope, and measure the

voltage between A/T-ECU connector C-12
terminal No.32 and earth.

OK: A wave pattern such as the one
shown on

P.23A-110

(Check Procedure

Using an Oscilloscope) should be output,
and the maximum value should be 4.8 V
or more and the minimum value should
be 0.8 V or less. There should be no noise
in the output wave pattern.

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Go to Step 19.

STEP 19. Connector check: C-12 A/T-ECU
connector
Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 20.

NO :

Repair the defective connector.

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-45

STEP 20. Replace the output shaft speed sensor
and then recheck the diagnosis code.
(1) Replace the output shaft speed sensor.
(2) Test drive the vehicle.
(3) Check if the diagnosis code is set.

Q: Is diagnosis code P1767 set?

YES :

Go to Step 21.

NO :

The inspection is complete.

STEP 21. Check the output shaft <4A/T> or direct
planetary carrier <5A/T>.
Visually check the output shaft <4A/T> or direct plan-
etary carrier <5A/T> for damage.

Q: Is the check result normal?

YES :

Eliminate the cause of the noise.

NO :

Replace the output shaft <4A/T> or direct
planetary carrier <5A/T>.

TROUBLESHOOTING

AUTOMATIC TRANSMISSION

23A-46

Code No.P1770 (P0705) Inhibitor switch system <4A/T>

AC903906

IGNITION
SWITCH (IG1)

INHIBITOR
SWITCH

A/T-ECU

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

Inhibitor Switch System Circuit