1999 MITSUBISHI LANCER EVOLUTION VI Workshop Manual

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.

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.

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.

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.

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.

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

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

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-42
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection procedure 1
Communication with the MUT-II is not possible.Probable cause
If communication with all other systems is not possible, there is a high
possibility that there is a malfunction of the diagnosis line. If communication
with only the A/C is not possible, the cause is probably a malfunction of the
diagnosis line or of the A/C-ECU power supply system (earth).
Malfunction of connector or harness

Malfunction of A/C-ECU
Is communication between MUT-II and
other system possible?NOCheck the MUT-II diagnosis line, and
repair if necessary.
YES
Measure at the diagnosis connector
B-22.

Voltage between terminal (11)
and body earth
OK:Indication fluctuates be-
tween 0 V and 12 V.OKMeasure at the A/C-ECU connector
B-04.

Disconnect the connector, and
measure at the harness side
connector.

Voltage between terminal (18)
and body earth
OK:System voltage – 2 VNGCheck the following connector:
B-04
OK
Check the trouble symptom.
NG
Repair
NG
Measure at the A/C-ECU connector
B-04.

Connect the connector.

Voltage between terminal (17)
and body earth
OK:Indication fluctuates be-
tween 0 V and 12 V.NGOKCheck the following connector:
B-04
NG
Check the harness between the diagno-
sis connector and the A/C-ECU, and
repair if necessary.
NG
Repair
OK
Check the harness between the diagno-
sis connector and the A/C-ECU.NG
RepairOK
Check the trouble symptom.
OK
Check the following connectors:
B-04, B-22NG
Repair
OK
Check the trouble symptom.
NG
Measure at the A/C-ECU connector
B-05.

Disconnect the connector, and
measure at the harness side
connector.

Voltage between terminal (28)
and body earth
OK:System voltageNGCheck the following connectors:
B-49, B-75NG
Repair
OK
Check the trouble symptom.NGCheck the harness between the junc-
tion block and the A/C-ECU, and repair
if necessary.
OK
Measure at the A/C-ECU connector
B-05.

Disconnect the connector, and
measure at the harness side
connector.

Continuity between terminals
(29), (35) and body earth
OK:ContinuityNGCheck the following connectors:
B-05, B-48, B-19, B-67, B-80NG
Repair
OK
Check the trouble symptom.NGCheck the harness between the
A/C-ECU and the body earth, and repair
if necessary.
OK
Replace the A/C-ECU.
NG
Replace the A/C-ECU.