Mitsubishi Grandis. Manual — part 849

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-63

• The engine-A/T-ECU energises or deenergises

solenoid valve, based on input signals such as
throttle position sensor opening angle, inhibitor
switch, etc.

DIAGNOSIS CODE SET CONDITIONS

If the drive terminal voltage of the low-reverse
solenoid valve is 3.0 V or less, it is judged that there
is a short circuit or open circuit in the low-reverse
solenoid valve, and diagnosis code 31 is set.
If diagnosis code 31 is set 4 times, the transmission
is fixed in 3rd as a fail-safe measure.

POSSIBLE CAUSES

• Malfunction of low-reverse solenoid valve

• Damaged harness wires and connectors

• Malfunction of the engine-A/T-ECU

DIAGNOSIS

STEP 1. MUT-III diagnosis code

Q: Is diagnosis code 36 set?

YES :

Go to Step 9.

NO :

Go to Step 2.

STEP 2. MUT-III actuator test

Item 01: Low-reverse solenoid valve

OK: Operating sound can be heard.

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 3.

STEP 3. Connector check: B-109 A/T control
solenoid valve assembly connector

Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the defective connector.

STEP 4. Measure the resistance at A/T control
solenoid valve assembly connector B-109.

Disconnect the connector, and measure the
resistance between terminal No.6 and No.10 at the
solenoid valve side.

OK: 2.7

− 3.4 Ω (A/T fluid temperature 20°C)

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Check the low-reverse solenoid valve and
solenoid valve harness.

STEP 5. Measure the voltage at engine-A/T-ECU
connector C-114.
(1) Connect A/T control solenoid valve assembly

connector B-109.

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

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

connector C-114 terminal No.128 and earth.

OK: System voltage

Q: Is the check result normal?

AC303628

B-109 (GR)

Harness side

AG

Connector: B-109

AC303628AF

B-109 (GR)

Connector: B-109

Sensor side

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

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-64

YES :

Go to Step 8.

NO :

Go to Step 6.

STEP 6. 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 7.

NO :

Repair the defective connector.

STEP 7. Check the harness between A/T control
solenoid valve assembly connector B-109
terminal No.6 and engine-A/T-ECU connector
C-114 terminal No.128.

Check the output line for short or open circuit.

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

Repair the wiring harness.

STEP 8. MUT-III actuator test

• Item 01: Low-reverse solenoid valve

OK: Operating sound can be heard.

Q: Is the check result normal?

YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-5

).

NO :

Replace the engine-A/T-ECU.

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

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

AC303628

B-109 (GR)

Harness side

AG

Connector: B-109

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

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-65

STEP 9. Connector check: B-109 A/T control
solenoid valve assembly connector

Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 10.

NO :

Repair the defective connector.

STEP 10. Measure the resistance at A/T control
solenoid valve assembly connector B-109.

Disconnect the connector, and measure the
resistance between terminal No.6 and No.10 at the
solenoid valve side.

OK: 2.7

− 3.4 Ω (A/T fluid temperature 20°C)

Q: Is the check result normal?

YES :

Go to Step 11.

NO :

Check the solenoid valve harness.

STEP 11. Connector check: B-14X A/T control
relay connector

Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 12.

NO :

Repair the defective connector.

STEP 12. Check the harness between A/T control
solenoid valve assembly connector B-109
terminal No.10 and A/T control relay connector
B-14X terminal No.1.

Check the power supply line for short or open circuit.

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

Repair the wiring harness.

Code No.32: Underdrive solenoid valve system

SOLENOID VALVE SYSTEM CIRCUIT

Refer to

P.23A-62

.

AC303628

B-109 (GR)

Harness side

AG

Connector: B-109

AC303628AF

B-109 (GR)

Connector: B-109

Sensor side

AC311979AC

B-14X

Connector: B-14X

Front of
vehicle

Relay box
side

AC303628

B-109 (GR)

Harness side

AG

Connector: B-109

AC311979AC

B-14X

Connector: B-14X

Front of
vehicle

Relay box
side

TROUBLESHOOTING <A/T>

AUTOMATIC TRANSMISSION (FF)

23A-66

OPERATION

• Solenoid valve closes or opens according to the

signals from the engine-A/T-ECU.

• The engine-A/T-ECU energises or deenergises

solenoid valve, based on input signals such as
throttle position sensor opening angle, inhibitor
switch, etc.

DIAGNOSIS CODE SET CONDITIONS

If the drive terminal voltage of the underdrive
solenoid valve is 3.0 V or less, it is judged that there
is a short-circuit or open circuit in the solenoid valve,
and diagnosis code 32 is set.
If diagnosis code 32 is set 4 times, the transmission
is fixed in 3rd as a fail-safe measure.

POSSIBLE CAUSES

• Malfunction of underdrive solenoid valve

• Damaged harness wires and connectors

• Malfunction of the engine-A/T-ECU

DIAGNOSIS

STEP 1. MUT-III diagnosis code

Q: Are diagnosis codes 33 and 34 set?

YES :

Go to Step 9.

NO :

Go to Step 2.

STEP 2. MUT-III actuator test

Item 02: Underdrive solenoid valve

OK: Operating sound can be heard.

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 3.

STEP 3. Connector check: B-109 A/T control
solenoid valve assembly connector

Check for the contact with terminals.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the defective connector.

STEP 4. Measure the resistance at A/T control
solenoid valve assembly connector B-109.

Disconnect the connector, and measure the
resistance between terminal No.3 and No.9 at the
solenoid valve side.

OK: 2.7

− 3.4 Ω (A/T fluid temperature 20°C)

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Check the underdrive solenoid valve.

STEP 5. Measure the voltage at engine-A/T-ECU
connector C-114.
(1) Connect A/T control solenoid valve assembly

connector B-109.

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

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

AC303628

B-109 (GR)

Harness side

AG

Connector: B-109

AC303628AF

B-109 (GR)

Connector: B-109

Sensor side

AC311284 AI

Connector: C-114 <LHD>

Connector: C-114 <RHD>

Engine-A/T-ECU

C-114 (GR)

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