1999 MITSUBISHI LANCER EVOLUTION VI ECU

HEATER AND MANUAL AIR CONDITIONER – Troubleshooting55-5
No.Trouble symp-
tomProblem causeRemedyRefer-
ence
page
1When the igni-
tion switch is
“ON”, the A/C
does not oper
Refrigerant leak or overfilling of refriger-
antReplenish the refrigerant, repair the
leak or take out some of the
refrigerant55-6
does not oper-
ate.A/C compressor relay is defectiveReplace the A/C compressor relay55-14ate.
A/C compressor magnetic clutch is
defectiveReplace the A/C compressor magnet
clutch55-26
Dual pressure switch is defectiveReplace the dual pressure switch55-13
A/C switch is defectiveReplace the A/C switch55-17
Blower switch is defectiveReplace the blower switch55-17
Air thermo-sensor is defectiveReplace the air thermo-sensor55-22
Refrigerant temperature switch is defec-
tiveReplace the refrigerant temperature
switch55-25
Automatic compressor-ECU is defectiveReplace the automatic compressor-
ECU–
2When the A/C is
operating, tem-
perat re inside
Refrigerant leakReplenish the refrigerant and repair
the leak55-6
perature inside
the
passengerDual pressure switch is defectiveReplace the dual pressure switch55-13the passenger
compartment
doesn’tde-Air thermo-sensor is defectiveReplace the air thermo-sensor–doesnt de-
crease (cool air
is not emitted)
Condenser fan relay is defectiveReplace the condenser fan relay55-14
is not emitted).Condenser fan motor is defectiveReplace the condenser fan motor55-29
Radiator fan relay (HI, LO) is defectiveReplace the radiator fan relay (HI, LO)55-14
Radiator fan motor is defectiveReplace the radiator fan motor–
Refrigerant temperature switch is defec-
tiveReplace the refrigerant temperature
switch55-25
Automatic compressor-ECU is defectiveReplace the automatic compressor-
ECU–
3Blower fan mo-
tor doesn’t turn
Blower switch is defectiveReplace the blower switch55-17
tor doesn’t turn.Blower relay is defectiveReplace the blower relay55-13
Resistor is defectiveReplace the resistor55-21
Blower fan motor is defectiveReplace the blower fan motor55-21
4Blower fan mo-
tor doesn’t stop
t rning
Defective harness between the blower
fan motor and the blower switchRepair the harness–
turning.Blower switch is defectiveReplace the blower switch55-17
Resistor is defectiveReplace the resistor55-21
5When the A/C is
operating con
Condenser fan relay is defectiveReplace the condenser fan relay55-14
operating con-
denser fan orCondenser fan motor is defectiveReplace the condenser fan motor55-29denser an or
radiator fan
does not runRadiator fan relay (HI, LO) is defectiveReplace the radiator fan relay (HI, LO)55-14does not run.
Radiator fan motor is defectiveReplace the radiator fan motor–
Dual pressure switch is defectiveReplace the dual pressure switch55-13
Engine-ECU is defectiveReplace the engine-ECU–

HEATER AND MANUAL AIR CONDITIONER –
Troubleshooting /
On-vehicle Service55-6
INSPECTION AT THE AUTOMATIC COMPRESSOR-ECU TERMINAL
Terminal
No.Check itemChecking requirementsNormal condition
1Output from ECU to A/C compressor
relay
A/C compressor relay: OFFSystem voltage
relay
A/C compressor relay: ON0 V
2Input from A/C switch to ECUA/C switch: OFF0 V
A/C switch: ONSystem voltage
3EarthAlways0 V
ON-VEHICLE SERVICE
REFRIGERANT CHARGING
Caution
The refrigerant generates toxic gases when it is expored
to a heat source such as fire. Keep flames away from
the refrigerant. Perform refrigerant charging at a
well-ventilated place.
1. Recommended charging tools
The following commercially available tools are recommended
for discharging and charging refrigerant.

Gas charging set [No. EA95 (R134a)]

Gas charging set case [No. EA101CS-2]

Gauge manifold [No. EA101N-1]

Charging valve [No. EA108N]

Adapter valve [No. EA104AD-3]
NOTE
The adapter valve opens when the handle is turned
clockwise and closes when it is turned counter-clockwise.

Quick joint (for low pressure) [No. EA413L]

Quick joint (for high pressure) [No. EA413H]

Charging hose (red) [No. EA104N-1]

Charging hose (blue) [No. EA104N-2]

Charging hose (yellow) [No. EA104N-3]

Vacuum pump [No. EA112A]

Vacuum pump adaptor [No. EA112X]
Gauge manifold
Adapter valve
(for low pressure)
Charging hoseVacuum
pump adaptor
Quick joint
(for low pressure)Charging valve
Quick joint
(for high pressure)
Vacuum pump

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.

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.