Mitsubishi L200. Manual - part 871

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-13

Code No.B1041,B1042: Potentiometer system for the air mixing damper

Air Mixing Damper Control Motor And Potentiometer Circuit 

AIR MIXING DAMPER
CONTROL MOTOR AND
POTENTIOMETER

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

DIAGNOSIS CODE SET CONDITION
This code is set when the air mixing damper control 
motor potentiometer does not send any signal to the 
A/C-ECU due to short or open circuit.

POSSIBLE CAUSES

• Malfunction of the air mixing damper control 

motor and potentiometer

• Damaged the wiring harness or connectors

• Malfunction of the automatic A/C control panel (A/

C-ECU)

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-44 A/C-ECU 
connector and C-49 air mixing damper control 
motor and potentiometer connector

AC509611BV

Harness side

C-49 (B)

C-49

C-44

Harness side

C-44

Connectors: C-44, C-49 <LHD>

AC509932BZ

Harness side

C-49 (B)

C-49

C-44

Harness side

C-44

Connectors: C-44, C-49 <RHD>

Q: Is the check result normal?

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-14

YES : 

Go to Step 2.

NO : 

Repair the connector.

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-15

STEP 2. Check the wiring harness between C-44 
A/C-ECU connector (terminals 34, 32 and 38) and 
C-49 air mixing damper control motor and 
potentiometer connector (terminals 6, 2 and 5).

AC509612 AD

Harness side

C-49 (B)

C-49

C-44

Harness side

C-44

Connectors: C-44, C-49, C-137, C-138 <LHD>

C-137 (L)

C-138 (L)

C-137

C-138

AC509933AC

Harness side

C-49 (B)

C-49

C-44

Harness side

C-44

Connectors: C-44, C-49, C-137, C-138 <RHD>

C-137 (L)

C-138 (L)

C-137

C-138

NOTE: Prior to the wiring harness inspection, check 
joint connector C-138 and C-137, and repair if neces-
sary.

• Check the potentiometer power supply, earth and 

signal line for open and short circuit.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the wiring harness.

STEP 3. Check the air mixing damper control 
motor and potentiometer.
Refer to 

P.55B-97

.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the air mixing damper control 
motor and potentiometer.

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 ).

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-16

Code No.B1045: Motor drive system for the air mixing damper <LHD>

AIR MIXING DAMPER CONTROL
MOTOR AND POTENTIOMETER

Air Mixing Damper Control Motor And Potentiometer 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

MOTOR DRIVE 
CIRCUIT

AC900842

A/C-ECU

DIAGNOSIS CODE SET CONDITION
This code is set when the air mixing damper cannot 
be rotated to the preset opening angle.

POSSIBLE CAUSES

• Malfunction of the air mixing damper control 

motor and potentiometer

• Malfunction of the automatic A/C control panel (A/

C-ECU)

• Damaged the wiring harness or connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-43,C-44 A/C-ECU 
connector and C-49 air mixing damper control 
motor and potentiometer connector

AC805686

Connectors: C-43, C-44, C-49

Harness side

C-44

C-43

C-44

AP

Harness side

C-43

C-49 (B)

Harness side

C-49

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the connector.

STEP 2. Check the wiring harness between A/C-
ECU connector C-43 terminal No.2, C-44 terminal 
No.41 and C-49 air mixing damper control motor 
and potentiometer connector (terminals 1 and 3).

AC805686

Connectors: C-43, C-44, C-49

Harness side

C-44

C-43

C-44

AP

Harness side

C-43

C-49 (B)

Harness side

C-49

• Check the motor activating lines for open and 

short circuit.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the wiring harness.

STEP 3. Check the air mixing damper control 
motor and potentiometer.
Refer to 

P.55B-97

.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the air mixing damper control 
motor and potentiometer.