Mitsubishi Grandis. Manual — part 842

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-35

STEP 16. Connector check: C-112
engine-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 input shaft
speed sensor connector B-112 terminal No.2 and
engine-A/T-ECU connector C-112 terminal No.64.

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
input shaft speed sensor at engine-A/T-ECU
connector C-112 (using an oscilloscope).
(1) Shift the selector lever to the D range.
(2) Accelerate the vehicle to approximately 50 km/h

AC311284

Connector: C-112 <LHD>

Connector: C-112 <RHD>

Harness side

Engine-A/T-ECU

C-112 (GR)

C-112 (GR)

Engine-A/T-ECU

AG

AC302452

Battery tray

B-112 (B)

Harness side

Connector: B-112

AG

AC311284

Connector: C-112 <LHD>

Connector: C-112 <RHD>

Harness side

Engine-A/T-ECU

C-112 (GR)

C-112 (GR)

Engine-A/T-ECU

AG

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-36

(shift range; 3rd).

(3) Connect an oscilloscope, and measure the

voltage between engine-A/T-ECU connector
C-112 terminal No.64 and earth.

OK: A wave pattern such as the one
shown on

P.23A-123

(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-112
engine-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.

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

Q: Is diagnosis code 22 set?

YES :

Go to Step 21.

NO :

The inspection is complete.

STEP 21. Underdrive clutch retainer inspection

Visually check the underdrive clutch retainer for
damage.

Q: Is the check result normal?

YES :

Eliminate the cause of the noise.

NO :

Replace the underdrive clutch retainer.

AC311284

Connector: C-112 <LHD>

Connector: C-112 <RHD>

Harness side

Engine-A/T-ECU

C-112 (GR)

C-112 (GR)

Engine-A/T-ECU

AG

AC311284

Connector: C-112 <LHD>

Connector: C-112 <RHD>

Harness side

Engine-A/T-ECU

C-112 (GR)

C-112 (GR)

Engine-A/T-ECU

AG

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-37

Code No.23: Output shaft speed sensor system

ENGINE-
A/T-ECU

OUTPUT SHAFT
SPEED SENSOR

IGNITION
SWITCH (IG1)

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

Output shaft speed sensor system circuit

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-38

OPERATION

The output shaft speed sensor detects the speed of
the transfer drive gear, and sends the information to
the engine-A/T-ECU as a pulse signal.

DIAGNOSIS CODE SET CONDITIONS

If the output pulse from the output shaft speed
sensor 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 23 is set.
If the code No.23 is set four times, the transmission
will be fixed in 3rd gear as a fail-safe measure.
However, the transmission can be downshifted to
2nd gear by operating the selector lever.

POSSIBLE CAUSES

• Malfunction of output shaft speed sensor

• Malfunction of transfer drive gear or driven gear

• Damaged harness wires and connectors

• Malfunction of the engine-A/T-ECU

DIAGNOSIS

STEP 1. MUT-III data list

Item 0002: Output shaft speed sensor (Refer to data
list reference table

P.23A-117

).

Q: Is the check result normal?

YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-5

).

NO :

Go to Step 2.

STEP 2. Connector check: B-108 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-108.

Disconnect the connector, and measure the
resistance between terminal 1 and earth at the wiring
harness side.

OK: 2

Ω or less

Q: Is the check result normal?

YES :

Go to Step 9.

NO :

Go to Step 4.

STEP 4. Measure the voltage at engine-A/T-ECU
connector C-112.
(1) Connect output shaft speed sensor connector

B-108.

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

(3) Measure the voltage between engine-A/T-ECU

connector C-112 terminal No.88 and earth.

OK: 0.5 V or less

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Go to Step 5.

AC302452AH

B-108 (GR)

Connector: B-108

Harness side

AC302452AH

B-108 (GR)

Connector: B-108

Harness side

AC311284

Connector: C-112 <LHD>

Connector: C-112 <RHD>

Harness side

Engine-A/T-ECU

C-112 (GR)

C-112 (GR)

Engine-A/T-ECU

AG