1999 MITSUBISHI LANCER EVOLUTION VI air condition
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FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-34
TROUBLESHOOTING
STANDARD FLOW OF DIAGNOSTIC TROUBLESHOOTING
Refer to GROUP 00 – How to Use Troubleshooting/Inspection Service Points.
DIAGNOSIS FUNCTION
DIAGNOSIS CODES CHECK
Connect the MUT-II or a voltmeter to the diagnosis connector (16-pin), then check diagnosis codes.
(Refer to GROUP 00 – How to Use Troubleshooting/Inspection Service Points.)
ERASING DIAGNOSIS CODES
Refer to GROUP 00 – How to Use Troubleshooting/Inspection Service Points.
INSPECTION CHART FOR DIAGNOSIS CODES
Code No.Diagnosis itemReference
page
11Inside air temperature sensor system (open circuit)55-34
12Inside air temperature sensor system (short circuit)55-34
13Outside air temperature sensor system (open circuit)55-35
14Outside air temperature sensor system (short circuit)55-35
15Heater water temperature sensor system (open circuit)55-36
16Heater water temperature sensor system (short circuit)55-36
21Air thermo sensor system (open circuit)55-37
22Air thermo sensor system (short circuit)55-37
31Potentiometer system of air mix damper assembly55-38
32Potentiometer system of air outlet changeover damper assembly55-39
41Drive system of air mix damper motor assembly55-40
42Drive system of air outlet changeover damper motor assembly55-40
INSPECTION PROCEDURES FOR DIAGNOSIS CODES
Code No.11 Inside air temperature sensor system (open
circuit)Probable cause
This diagnosis code is output if the power supply line or input line of the inside
air temperature sensor inside A/C-ECU is open-circuited and no signal is input
from the inside air temperature sensor to A/C-ECU.Malfunction of the A/C-ECU
Replace the A/C-ECU.
Code No.12 Inside air temperature sensor system (short
circuit)Probable cause
This diagnosis code is output if the power supply line or input line of the inside
air temperature sensor inside A/C-ECU is short-circuited and inside air
temperature sensor power supply voltage signals are input to A/C-ECU.Malfunction of the A/C-ECU
Replace the A/C-ECU.
Page 425 of 558
FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-35
Code No.13 Outside air temperature sensor system (open
circuit)Probable cause
This diagnosis code is output if the power supply line or input line of the outside
air temperature sensor is open-circuited and no signal is input from the outside
air temperature sensor to A/C-ECU.Malfunction of the outside air temperature sensor
Malfunction of connector, harness
Malfunction of the A/C-ECU
Outside air temperature sensor check (Refer to P.55-62.)NG
Replace
OK
Measure at the outside air temperature sensor connector A-35.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (2) and body earth
OK:5 VNGCheck the following connectors:
B-15, B-16
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the outside air temperature sensor
and the A/C-ECU.
NG
Repair OK
Replace the A/C-ECU.
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Voltage between terminal (7) and body earth
OK:2.3 – 2.9 VNGCheck the following connectors:
A-15, B-04
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the outside air temperature sensor
and the A/C-ECU, and repair if necessary.
OK
Check the following connector: B-04NG
Repair
OK
Check the trouble symptom.NGReplace the A/C-ECU.
Code No.14 Outside air temperature sensor system (short
circuit)Probable cause
This diagnosis code is output if the power supply line or input line of the outside
air temperature sensor is short-circuited and outside air temperature sensor power
supply voltage signals are input to A/C-ECU.Malfunction of the outside air temperature sensor
Malfunction of connector, harness
Malfunction of the A/C-ECU
Outside air temperature sensor check (Refer to P.55-62.)NG
Replace
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Voltage between terminal (7) and body earth
OK:2.3 – 2.9 VNGCheck the harness between the outside air temperature sensor
and the A/C-ECU, and repair if necessary.
OK
Replace the A/C-ECU.
Page 426 of 558
FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-36
Code No.15 Heater water temperature sensor system
(open circuit)Probable cause
This diagnosis code is output if the power supply line or input line of the heater
water temperature sensor is open-circuited and no heater water temperature sensor
signals are input to A/C-ECU.Malfunction of the heater water temperature
sensor
Malfunction of connector, harness
Malfunction of the A/C-ECU
Heater water temperature sensor check (Refer to P.55-64.)NG
Replace
OK
Measure at the heater water temperature sensor connector B-02.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (1) and body earth
OK:5 VNGCheck the following connector:
B-04
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the heater water temperature sensor
and the A/C-ECU.
NG
Repair OK
Replace the A/C-ECU.
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Voltage between terminal (4) and body earth
OK:2.3 – 2.9 VNGCheck the following connector:
B-02
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the heater water temperature sensor
and the A/C-ECU, and repair if necessary.
OK
Check the following connector: B-04NG
Repair
OK
Check the trouble symptom.NGReplace the A/C-ECU.
Code No.16 Heater water temperature sensor system
(short circuit)Probable cause
This diagnosis code is output if the power supply line or output line of the heater
water temperature sensor is short-circuited and heater water temperature sensor
power supply voltage signals are input to A/C-ECU.Malfunction of the heater water temperature
sensor
Malfunction of connector, harness
Malfunction of the A/C-ECU
Heater water temperature sensor check (Refer to P.55-64.)NG
Replace
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Voltage between terminal (4) and body earth
OK:2.3 – 2.9 VNGCheck the harness between the heater water temperature sensor
and the A/C-ECU, and repair if necessary.
OK
Replace the A/C-ECU.
Page 427 of 558
FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-37
Code No.21 Air thermo sensor system (open circuit)Probable cause
This diagnosis code is output if the power supply line or input line of the air thermo
sensor is open-circuited and no air thermo sensor signals are input to A/C-ECU.Malfunction of the air thermo sensor
Malfunction of connector, harness
Malfunction of the A/C-ECU
Air thermo sensor check (Refer to P.55-22.)NG
Replace
OK
Measure at the air thermo sensor connector B-03.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (2) and body earth
OK:5 VNGCheck the following connector:
B-04
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the air thermo sensor and the
A/C-ECU.
NG
Repair OK
Replace the A/C-ECU.
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Voltage between terminal (8) and body earth
OK:2.3 – 2.9 VNGCheck the following connector:
B-03
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the air thermo sensor and the
A/C-ECU, and repair if necessary.
OK
Check the following connector: B-04NG
Repair
OK
Check the trouble symptom.NGReplace the A/C-ECU.
Code No.22 Air thermo sensor system (short circuit)Probable cause
This diagnosis code is output if the power supply line or output line of the air thermo
sensor is short-circuited and air thermo sensor power supply voltage signals are
input to A/C-ECU.Malfunction of the air thermo sensor
Malfunction of connector, harness
Malfunction of the A/C-ECU
Air thermo sensor check (Refer to P.55-22.)NG
Replace
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Voltage between terminal (8) and body earth
OK:2.3 – 2.9 VNGCheck the harness between the air thermo sensor and the
A/C-ECU, and repair if necessary.
OK
Replace the A/C-ECU.
Page 428 of 558
FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-38
Code No.31 Potentiometer system of air mix damper motor
assemblyProbable cause
This diagnosis code is output if no signals are input from air mix damper potentiometer
to A/C-ECU because of short-circuit or open-circuit in the harness.Malfunction of the air mix damper potentiometer
Malfunction of connector, harness
Malfunction of the A/C-ECU
Air mix damper potentiometer check (Refer to P.55-59.)NG
Replace
OK
Measure at the air mix damper potentiometer connector B-39.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (6) and body earth
OK:5 VNGCheck the following connector:
B-04
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the air mix damper potentiometer
and the A/C-ECU.
NG
Repair OK
Replace the A/C-ECU.
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Air mix damper position: MAX.HOT
Voltage between terminal (5) and body earth
OK:4.7 – 5.0 VNGCheck the following connector:
B-39
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the air mix damper potentiometer
and the A/C-ECU, and repair if necessary.
OK
Check the following connector: B-04NG
Repair
OK
Check the trouble symptom.NGReplace the A/C-ECU.
Page 429 of 558
FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-39
Code No.32 Potentiometer system of air outlet changeover
damper motor assemblyProbable cause
This diagnosis code is output if no signals are input from air outlet changeover
damper potentiometer to A/C-ECU because of short-circuit or open-circuit in the
harness.Malfunction of the air outlet changeover damper
potentiometer
Malfunction of connector, harness
Malfunction of the A/C-ECU
Air outlet changeover damper potentiometer check (Refer to
P.55-60.)NG
Replace
OK
Measure at the air outlet changeover damper potentiometer con-
nector B-06.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (2) and body earth
OK:5 VNGCheck the following connector:
B-04
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the air outlet changeover damper
potentiometer and the A/C-ECU.
NG
Repair OK
Replace the A/C-ECU.
OK
Measure at the A/C-ECU connector B-04.
Connect the connector.
Air outlet changeover damper position: DEF
Voltage between terminal (6) and body earth
OK:4.8 – 5.2 VNGCheck the following connector:
B-06
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the air outlet changeover damper
motor potentiometer and the A/C-ECU, and repair if necessary.
OK
Check the following connector: B-04NG
Repair
OK
Check the trouble symptom.NGReplace the A/C-ECU.
Page 430 of 558
FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-40
Code No.41 Drive system of air mix damper motor
assemblyProbable cause
This diagnosis code is output if the air mix damper fails to be turned to the preset
opening.Malfunction of the air mix damper motor assembly
Malfunction of connector, harness
Malfunction of the A/C-ECU
Air mix damper motor check (Refer to P.55-59.)NG
Replace
OK
Check the following connectors:
B-39, B-05NG
Repair
OK
Check the trouble symptom.NGCheck the harness between the air mix damper motor and the
A/C-ECU.
OK
Replace the A/C-ECU.
NG
Repair
Code No.42 Drive system of air outlet changeover damper
motor assemblyProbable cause
This diagnosis code is output if the air outlet changeover damper fails to be turned
to the preset opening.Malfunction of the air outlet changeover damper
motor assembly
Malfunction of connector, harness
Malfunction of the A/C-ECU
Air outlet changeover damper motor check (Refer to P.55-60.)NG
Replace
OK
Check the following connectors:
B-06, B-05NG
Repair
OK
Check the trouble symptom.NGCheck the harness between the air outlet changeover damper
motor and the A/C-ECU.
OK
Replace the A/C-ECU.
NG
Repair
Page 431 of 558
FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-41
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptomInspection proce-
dure No.Reference page
Communication with the MUT-II is not possible.155-42
Air conditioner does not operate.255-43
A/C graphic display on control panel is blank.355-44
Temperature cannot be set.455-44
A/C outlet air temperature does not increase.555-44
A/C outlet air temperature does not decrease.655-44
Blower does not operate.755-45
Blower does not operate in HI mode.855-46
Blower air amount cannot be changed.955-47
Air outlet port cannot be changed.1055-47
Inside/outside air changeover is not possible.1155-48
Defroster function does not operate.1255-49
Condenser fan does not operate.1355-50
Rear defogger does not operate.1455-51
A/C-ECU power supply circuit check1555-52
A/C compressor control circuit check1655-53