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Mitsubishi Grandis. Manual - part 855

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-87

STEP 12. Connector check: C-114
engine-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
relay connector B-14X terminal No.1 and
engine-A/T-ECU connector C-114 terminal
No.123, 124.

Check the power supply line for short or open circuit.

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Repair the wiring harness.

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

Engine-A/T-ECU

Harness side

124 123

130

131

132

133
141 140 139 138
146 145

129
137

128
136

127126

135
143

121
125
134
142

144

122

AC311979AC

B-14X

Connector: B-14X

Front of
vehicle

Relay box
side

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

Engine-A/T-ECU

Harness side

124 123

130

131

132

133
141 140 139 138
146 145

129
137

128
136

127126

135
143

121
125
134
142

144

122

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-88

STEP 14. Connector check: C-114
engine-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 A/T control
relay connector B-14X terminal No.2 and
engine-A/T-ECU connector C-114 terminal
No.127.

Check the output line for short or open circuit.

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Repair the wiring harness.

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

Engine-A/T-ECU

Harness side

124 123

130

131

132

133
141 140 139 138
146 145

129
137

128
136

127126

135
143

121
125
134
142

144

122

AC311979AC

B-14X

Connector: B-14X

Front of
vehicle

Relay box
side

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

Engine-A/T-ECU

Harness side

124 123

130

131

132

133
141 140 139 138
146 145

129
137

128
136

127126

135
143

121
125
134
142

144

122

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-89

INSPECTION CHART FOR TROUBLE
SYMPTOMS

M1231008000341

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 2: Engine does not start

COMMENTS ON TROUBLE SYMPTOM

If the engine does not start when the selector lever is
in P or N position, the cause is probably a
malfunction of inhibitor switch system, transmission
control cable, engine system, torque converter or oil
pump.

POSSIBLE CAUSES

• Malfunction of inhibitor switch

• Malfunction of transmission control cable

• Malfunction of engine system

• Malfunction of torque converter

• Malfunction of oil pump

• Malfunction of the engine-A/T-ECU

DIAGNOSIS

STEP 1. MUT-III diagnosis code

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

Q: Are diagnosis codes 27 or 28 output?

Trouble symptom

Inspection
procedure No.

Reference page

Communication with the MUT-III is not possible

Refer to GROUP
13,
Troubleshooting

P.13A-283

Driving not possible

Engine does not start

P.23A-89

Does not move forward

P.23A-90

Does not move backward

P.23A-91

Does not move (forward or backward)

P.23A-92

Malfunction when
starting off

Engine stalls during shifting

P.23A-93

Shift shock when shifting from N to D and
long delay

P.23A-93

Shift shock when shifting from N to R and
long delay

P.23A-94

Shift shock when shifting from N to D, N to
R and long delay

P.23A-95

Problem during
shifting

Shift shock and slipping

P.23A-96

Incorrect shift points Does not shift properly (all point)

P.23A-97

Does not shift properly (some point)

P.23A-98

No shifting

Does not shift (no diagnosis code)

P.23A-98

Problem during
driving

Poor acceleration

P.23A-98

Vibration

P.23A-99

Shift switch assembly system

P.23A-100

Abnormal shift indicator display

P.23A-116

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-90

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. Transmission control cable check

Check the transmission control cable and inhibitor
switch for installation condition.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Adjust the positions of the transmission
control cable and inhibitor switch (Refer to

P.23A-128

STEP 3. Engine system check

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the engine system.

STEP 4. 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 5.

NO :

The inspection is complete.

STEP 5. Torque converter check

Check for damaged drive plate, incorrect installation
in the input shaft (inserted at an angle) or damaged
splines.

Q: Is the check result normal?

YES :

Check the oil pump for incorrect installation,

damage and etc., and replace the oil pump
assembly if necessary (The oil pump cannot
be disassembled).

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.

INSPECTION PROCEDURE 3: Does not move forward

COMMENTS ON TROUBLE SYMPTOM

If the vehicle does not move forward when the
selector lever is shifted sport mode 1, or 2 range
while the engine is idling, the cause is probably
abnormal line pressure or a malfunction of the
underdrive clutch or valve body.

POSSIBLE CAUSES

• Malfunction of underdrive solenoid valve

• Malfunction of inhibitor switch

• Abnormal line pressure

• Malfunction of the underdrive clutch

• Malfunction of the valve body

• Malfunction of the oil pump

• Malfunction of the engine-A/T-ECU

DIAGNOSIS

STEP 1. MUT-III actuator test

Item 02: Underdrive solenoid valve

OK: Operating sound can be heard.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Replace the underdrive solenoid valve.

STEP 2. 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 3.

STEP 3. Underdrive solenoid valve check
(1) Turn the ignition switch to the ON position.
(2) Shift the selector lever from N to D range.
(3) Confirm the operating sound of the underdrive

solenoid valve.

OK: Operating sound can be heard.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Replace the engine-A/T-ECU.

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