Mitsubishi Lancer (4A9 engine). Manual — part 283

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-13

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-59 heater control
unit connector and C-118 fin thermo sensor
connector

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the connector.

STEP 2. Check the wiring harness between C-59
heater control unit connector (terminals 21 and
22) and C-118 fin thermo sensor connector
(terminals 2 and 1).

• Check the sensor signal line and earth line for

open or short circuit.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the wiring harness.

STEP 3. Check the fin thermo sensor.
Refer to .

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Replace the fin thermo sensor.

STEP 4. Check whether the diagnosis code is
reset.

Q: Is the diagnosis code set?

YES :

Replace the heater control unit.

NO :

The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction ).

Code No.B1031: Fin thermo Sensor system (short circuit) <Vehicles with A/C>

Code No.B1032: Fin thermo Sensor system (open circuit) <Vehicles with A/C>

Fin Thermo Sensor Circuit

FIN THERMO
SENSOR

A/C-ECU

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple SI : Silver

AC612706

Connectors: C-13, C-118 <LHD>

AD

C-13 (B)

C-118

AC612710

Connectors: C-13, C-118 <RHD>

AR

C-118

C-13 (B)

COMMENTS ON TROUBLE SYMPTOM
This code is set when the fin thermo sensor circuit is

short (Code No.B1031) or is open (Code No.B1032).

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-14

PROBABLE CAUSES

• Malfunction of the fin thermo sensor

• Damaged wiring harness or connectors

• Malfunction of the A/C-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-13 A/C-ECU
connector and C-118 fin thermo sensor
connector

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the connector.

STEP 2. Check the wiring harness between C-13
A/C-ECU connector (terminals 21 and 22) and C-
118 fin thermo sensor connector (terminals 2 and
1).

• Check the sensor signal line and earth line for

open or short circuit.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the wiring harness.

STEP 3. Check the fin thermo sensor.
Refer to .

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Replace the fin thermo sensor.

STEP 4. Check whether the diagnosis code is
reset.

Q: Is the diagnosis code set?

YES :

Replace the A/C-ECU.

NO :

The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction ).

Code No. B1000: Communication error with control panel <Vehicles without A/C>

Heater Control Panel Circuit

HEATER
CONTROL
UNIT

HEATER
CONTROL
PANEL

CPU

INTERFACE
CIRCUIT

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple SI : Silver

ACA00851

AC612706

Connectors: C-60, C-147 <LHD>

BP

C-60 (B)

C-147

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-15

COMMENTS ON TROUBLE SYMPTOM
This code will be set when the heater control unit
cannot receive information from the heater control
panel.

PROBABLE CAUSES

• Malfunction of the heater control panel

• Damaged wiring harness or connectors

• Malfunction of the heater control unit

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-147 heater control
panel connector and C-60 heater control unit
connector

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the connector.

STEP 2. Check the wiring harness between C-147
heater control panel connector terminal No. 9
and C-60 heater control unit connector terminal
No. 9.

• Check the heater control panel signal line for

open or short circuit.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the wiring harness.

STEP 3. Check whether the diagnosis code is
reset.
Replace the heater control panel, and erase the
diagnosis code. Then check that no diagnosis code
is being set.

Q: Is the diagnosis code set?

YES :

Replace the heater control unit.

NO :

The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction ).

Code No. B1000: Communication error with control panel <Vehicles with A/C>

A/C Control Panel Circuit

A/C-ECU

A/C
CONTROL
PANEL

CPU

INTERFACE
CIRCUIT

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple SI : Silver

ACA00799

AC612706

Connectors: C-15, C-119 <LHD>

AE

C-15 (B)

C-119

AC612710

Connector: C-15 <RHD>

AS

C-15 (B)

AC612711

Connector: C-119 <RHD>

AG

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-16

COMMENTS ON TROUBLE SYMPTOM
This code will be set when the A/C-ECU cannot
receive information from the A/C control panel.

PROBABLE CAUSES

• Malfunction of the A/C control panel

• Damaged wiring harness or connectors

• Malfunction of the A/C-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-119 A/C control
panel connector and C-15 A/C-ECU connector

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the connector.

STEP 2. Check the wiring harness between C-119
A/C control panel connector terminal No. 9 and
C-15 A/C-ECU connector terminal No. 9.

• Check the A/C control panel signal line for open

or short circuit.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the wiring harness.

STEP 3. Check whether the diagnosis code is
reset.
Replace the A/C control panel, and erase the diagno-
sis code. Then check that no diagnosis code is being
set.

Q: Is the diagnosis code set?

YES :

Replace the A/C-ECU.

NO :

The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction ).