Mitsubishi Grandis. Manual — part 853

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-79

DIAGNOSIS

STEP 1. MUT-III diagnosis code

Either of diagnosis codes 41, 42, 43, 44 or 46 is set,
the input shaft speed sensor or output shaft speed
sensor is defective.

Q: Are diagnosis codes 22 or 23 output?

YES <diagnosis code 22 is set> :

Refer to

diagnosis code 22 input shaft speed sensor
system

P.23A-27

.

YES <diagnosis code 23 is set> :

Refer to

diagnosis code 23 output shaft speed
sensor system

P.23A-37

.

NO :

Go to Step 2.

STEP 2. MUT-III diagnosis code

Either of diagnosis codes 41, 42, 43, 44 or 46 is set,
the corresponding solenoid valve is defective.

Q: Is either of diagnosis code 31, 32, 33, 34 output?

YES <diagnosis code 31 is set> :

Refer to

diagnosis code 31: Low-reverse solenoid
valve system

P.23A-62

.

YES <diagnosis code 32 is set> :

Refer to

diagnosis code 32: Underdrive solenoid
valve system

P.23A-65

.

YES <diagnosis code 33 is set> :

Refer to

diagnosis code 33: Second solenoid valve
system

P.23A-68

.

YES <diagnosis code 34 is set> :

Refer to

diagnosis code 34: Overdrive solenoid valve
system

P.23A-71

.

NO :

Go to Step 3.

STEP 3. Hydraulic pressure test

Each hydraulic pressure of the elements below,
which diagnosis codes indicate, should be within the
standard value.

• diagnosis code 41: Underdrive clutch,

low-reverse brake

• diagnosis code 42: Underdrive clutch, second

brake

• diagnosis code 43: Underdrive clutch, overdrive

clutch

• diagnosis code 44: Overdrive clutch, second

brake

• diagnosis code 46: Reverse clutch, low-reverse

brake

OK: Refer to Hydraulic Pressure Test

P.23A-133

.

Q: Is the check result normal?

YES :

Go to Step 6.

NO <some hydraulic pressures are abnormal> :

Go to Step 5.

NO <all hydraulic pressure are abnormal> :

Go to

Step 4.

STEP 4. Adjust the line pressure and recheck the
diagnosis code.

(1) Adjust the line pressure (Refer to

P.23A-138

).

(2) Test drive the vehicle.
(3) Check the diagnosis code.

Q: Is the diagnosis code set?

YES :

Go to Step 5.

NO :

The inspection is complete.

STEP 5. Disassemble, clean and assemble the
valve body and recheck the diagnosis code.
(1) Check the mounting bolts for looseness, and the

O-ring, solenoid valve and valve body for
damage.
Replace the valve body assembly if the damages
are thought to be irreparable.

(2) Test drive the vehicle.
(3) Check the diagnosis code.

Q: Is the diagnosis code set?

YES :

Go to Step 7.

NO :

The inspection is complete.

STEP 6. Replace the engine-A/T-ECU and then
recheck the diagnosis code.
(1) Replace the engine-A/T-ECU.
(2) Test drive the vehicle.
(3) Check the diagnosis code.

Q: Is the diagnosis code set?

YES :

Go to Step 7.

NO :

The inspection is complete.

STEP 7. Check the A/T internal clutch and brake,
and then recheck the diagnosis code.
(1) Check the following clutches or brakes according

to the output diagnosis codes, replace if

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-80

necessary.

• If diagnosis code 41, 42, 43 are set

individually or in a group, replace the
underdrive clutch.

• If diagnosis code 43, 44 are set individually or

in a group, replace the overdrive clutch.

• If diagnosis code 46 is set, replace the

reverse clutch.

• If diagnosis code 41, 46 are set individually or

in a group, replace the low-reverse brake.

• If diagnosis code 42, 44 are set individually or

in a group, replace the second brake.

• If diagnosis code 41 is set, replace the

one-way clutch.

(2) Test drive the vehicle.

(3) Check the diagnosis code.

Q: Is the diagnosis code set?

YES :

Eliminate the cause of the noise.

NO :

The inspection is complete.

Code No.52: Damper clutch system

OPERATION

The engine-A/T-ECU engages and disengages the
damper clutch (incorporated in the torque converter)
by operating the DCC solenoid valve in response to
driving conditions.

DIAGNOSIS CODE SET CONDITIONS

If the damper clutch solenoid valve drive duty ratio is
100% for a continuous period of 4 seconds or more
when the damper clutch starts operating, diagnosis
code 52 is set.

POSSIBLE CAUSES

• Malfunction of input shaft speed sensor

• Damaged harness wires and connectors

• Malfunction of the engine-A/T-ECU

• Malfunction of damper clutch solenoid valve

• Malfunction of valve body assembly

• Malfunction of torque converter

DIAGNOSIS

STEP 1. MUT-III diagnosis code

If diagnosis code 52 is set, the input shaft speed
sensor may be defective.

Q: Is diagnosis code 22 set?

YES :

Refer to diagnosis code 22: Input shaft

speed sensor system

P.23A-27

.

NO :

Go to Step 2.

STEP 2. MUT-III diagnosis code

If diagnosis code 52 is set, the damper clutch
solenoid valve may be defective.

Q: Is diagnosis code 36 set?

YES :

Refer to diagnosis code 36: Damper clutch

solenoid valve system

P.23A-74

.

NO :

Go to Step 3.

STEP 3. MUT-III data list

• Item 36: Damper clutch solenoid valve duty ratio

(Refer to data list reference table

P.23A-117

).

• Item 52: Damper clutch slip amount (Refer to

data list reference table

P.23A-117

).

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Go to Step 4.

STEP 4. Hydraulic pressure test

Measure the torque converter hydraulic pressure
(Refer to

P.23A-133

).

OK: Refer to Hydraulic Pressure Test

P.23A-133

.

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Go to Step 5.

STEP 5. Adjust the line pressure and recheck the
diagnosis code.

(1) Adjust the line pressure (Refer to

P.23A-138

).

(2) Test drive the vehicle.
(3) Check the diagnosis code.

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-81

Q: Is the diagnosis code set?

YES :

Go to Step 7.

NO :

The inspection is complete.

STEP 6. Replace the engine-A/T-ECU and then
recheck the diagnosis code.
(1) Replace the engine-A/T-ECU.
(2) Test drive the vehicle.
(3) Check the diagnosis code.

Q: Is the diagnosis code set?

YES :

Go to Step 7.

NO :

The inspection is complete.

STEP 7. Disassemble, clean and assemble the
valve body and recheck the diagnosis code.
(1) Check the mounting bolts for looseness, and the

O-ring, solenoid valve and valve body for
damage.
Replace the valve body assembly if the damages
are thought to be irreparable.

(2) Test drive the vehicle.
(3) Check the diagnosis code.

Q: Is the diagnosis code set?

YES :

Check the torque converter and replace it if

necessary.

NO :

The inspection is complete.

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-82

Code No.54: A/T control relay system

OPERATION

If a fail-safe operation is activated, the A/T control
relay shuts off the power supply to the solenoid valve
in accordance with the signal from the
engine-A/T-ECU.

DIAGNOSIS CODE SET CONDITIONS

Code No.54 will be set if the A/T control voltage is
less than 7 V after the ignition switch is turned on.

If code No.54 is set, the transmission will be held in
3rd gear.

POSSIBLE CAUSES

• Malfunction of A/T control relay

• Damaged harness wires and connectors

• Malfunction of the engine-A/T-ECU

BATTERY

A/T
CONTROL
RELAY

ENGINE-
A/T-ECU

IGNITION
SWITCH (IG1)

SOLENOID
VALVE POWER
SOURCE

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

A/T control relay system circuit

RELAY
BOX