Mitsubishi Grandis. Manual — part 858

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-99

STEP 2. Engine-A/T-ECU replacement
(1) Replace the engine-A/T-ECU.
(2) Test drive the vehicle.
(3) Verify that the condition described by the

customer exists.

Q: Does a malfunction take place again?

YES :

Go to Step 1.

NO :

The inspection is complete.

INSPECTION PROCEDURE 15: Vibration

COMMENTS ON TROUBLE SYMPTOM

If vibration occurs when driving at constant speed or
when acceleration in high range, the cause is
probably an abnormal torque converter pressure, or
a malfunction of the engine system, damper clutch
solenoid valve, valve body or torque converter.

POSSIBLE CAUSES

• Malfunction of damper clutch solenoid valve

• Malfunction of engine system

• Abnormal torque converter pressure

• Malfunction of valve body

• Malfunction of torque converter

• Malfunction of the engine-A/T-ECU

DIAGNOSIS

STEP 1. Check when the vibration occurs.

Q: Does the vibration occur when the damper clutch

is operating?
YES :

Go to Step 3.

NO :

Go to Step 2.

STEP 2. Engine system check

Q: Is the check result normal?

YES :

The inspection is complete.

NO :

Repair the engine system.

STEP 3. Engine-A/T-ECU replacement
(1) Replace the engine-A/T-ECU.
(2) Test drive the vehicle.
(3) Verify that the condition described by the

customer exists.

Q: Does a malfunction take place again?

YES :

Go to Step 4.

NO :

The inspection is complete.

STEP 4. Torque converter check
Check for damaged drive plate, incorrect installation
in the input shaft (inserted at an angle), damaged
splines or damper clutch sealing.

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

If repair is possible, repair the damaged
part. If repair is not possible because the
splines on the drive plate or torque
converter are damaged, replace it.

STEP 5. Valve body disassembly clean and
assembly
Check the bolts for looseness and the O-ring,
solenoid valves, springs and valve body for damage.

Q: Is the check result normal?

YES :

The inspection is complete.

NO :

Replace the valve body assembly if the
damages are thought to be irreparable.

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-100

INSPECTION PROCEDURE 16: Shift switch assembly system

Shift switch assembly system circuit <LHD>

IGNITION
SWITCH(IG1)

INHIBITOR
SWITCH

ENGINE-
A/T-ECU

SHIFT
SWITCH
ASSEMBLY

SHIFT
SWITCH

SELECT
SWITCH

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

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-101

OPERATION

The shift switch assembly detects the shift range
(sport mode) which the driver has selected, and
sends the information to the engine-A/T-ECU.

COMMENTS ON TROUBLE SYMPTOM

The cause is probably a malfunction of the shift
switch and engine-A/T-ECU.

Possible causes

• Malfunction of shift switch assembly

• Damaged harness wires and connectors

IGNITION
SWITCH(IG1)

INHIBITOR
SWITCH

ENGINE-
A/T-ECU

SHIFT
SWITCH
ASSEMBLY

SHIFT
SWITCH

SELECT
SWITCH

Shift switch assembly system circuit <RHD>

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

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-102

• Malfunction of the engine-A/T-ECU

DIAGNOSIS

STEP 1. MUT-III diagnosis code

Either of diagnosis codes 27 or 28 is set, inhibtor
switch is defective.

Q: Are diagnosis codes 27 or 28 output?

YES <diagnosis code 27 is set> :

Refer to

diagnosis code 27: Inhibitor switch system

P.23A-52

.

YES <diagnosis code 28 is set> :

Refer to

diagnosis code 28: Inhibitor switch system

P.23A-59

.

NO :

Go to Step 2.

STEP 2. MUT-III data list

• Item 67: Select switch

• Item 68: Upshift switch

• Item 69: Downshift switch

Check the above data list (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 <"NG" for all items> :

Go to Step 3.

NO <"NG" for items 68 and 69> :

Go to Step 5.

NO <"NG" for item 67> :

Go to Step 10.

NO <"NG" for item 68> :

Go to Step 17.

NO <"NG" for item 69> :

Go to Step 20.