B1446

Click here

DTC Code	DTC Name
B1446	Air Mix Damper Control Servo Motor Circuit (Driver Side)

Click here

DESCRIPTION

*1: for LHD
*2: for RHD

The No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on these signals to move the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix) to the appropriate position. As a result, the amount of air passing through the heater core after passing through the evaporator is adjusted, and the temperature of the air blowing toward the driver side is controlled.

The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory
B1446	Air Mix Damper Control Servo Motor Circuit (Driver Side)	Diagnosis condition: No. 2 air conditioning radiator damper servo sub-assembly1 or No. 4 air conditioning radiator damper servo sub-assembly2 (driver side upper air mix) operation Malfunction status: The damper servo operation request signal is output but the position information of the servo does not change or servo is malfunctioning Detection time: Continuously for 30 seconds or more	No. 2 air conditioning radiator damper servo sub-assembly1 (driver side upper air mix) No. 4 air conditioning radiator damper servo sub-assembly2 (driver side upper air mix) Air conditioning harness assembly Air conditioning amplifier assembly	Memorized

Table 1. DTC Detection Condition Combination Table
		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	No. 2 air conditioning radiator damper servo sub-assembly1 or No. 4 air conditioning radiator damper servo sub-assembly2 (driver side upper air mix) operation	○	○
Malfunction Status	The damper servo operation request signal is output but the position information of the servo does not change	○	-
Malfunction Status	The damper servo operation request signal is output but the position information of the servo is malfunctioning	-	○
Detection Time		Continuously for 30 seconds or more	Continuously for 30 seconds or more
Trip Count		1 trip	1 trip

Tip:

If the conditions match either of these patterns, a DTC will be output.

Figure 2. for RHD: B004UMQE63

Figure 1. for LHD:

Click here

WIRING DIAGRAM

Click here

CAUTION / NOTICE / HINT

Note:

Confirm that no mechanical problem is present because this diagnostic code can be output when either a damper link or the damper is mechanically locked.
When installing the damper servo motor, make sure to install it correctly.
When the servo motor is replaced, be sure to perform servo motor initialization.

Click here

Tip:

Confirm that no mechanical problem is present because this DTC can be output when either a damper link or damper is mechanically locked.

Click here

PROCEDURE

Click here

CHECK FOR DTC

Check for DTCs.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Result

Result	Proceed to
DTC B1446 is output	A
DTC B1446 and B1497 are output.	B

AClick here
B
GO TO DTC B1497Click here

Click here

CHECK AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY

Check for No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 is installed correctly.

OK
No. 2 air conditioning radiator damper servo sub-assembly1 or No. 4 air conditioning radiator damper servo sub-assembly2 is installed correctly.

*1: for LHD
*2: for RHD

Result

Result	Proceed to
OK	A
NG (for LHD)	B
NG (for RHD)	C

AClick here
B
REINSTALL NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLYClick here
C
REINSTALL NO. 4 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLYClick here

Click here

CHECK AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (MOTOR, LINK, DAMPER)

Check for a wire harness caught between the links of the motors and dampers.

OK
No wire harnesses are caught between the links of the motors and dampers.

Result

Proceed to
OK
NG

OKClick here
NG
REMOVE PINCHED WIRE HARNESS

Click here

CHECK AIR CONDITIONING RADIATOR ASSEMBLY (DAMPER)

Remove the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2.

Click here
- *1: for LHD
- *2: for RHD

Operate the dampers by hand.

OK
The dampers are easily operated by hand.

Result

Proceed to
OK
NG

OKClick here
NG
REPAIR OR REPLACE AIR CONDITIONING RADIATOR ASSEMBLY

Click here

PERFORM ACTIVE TEST USING GTS (COOL A/M SERVO PULSE(D))

*1: for LHD
*2: for RHD
*3: Actually operates the No. 2 air conditioning radiator damper servo sub-assembly (driver side upper air mix).

Remove the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2.

Click here
Connect the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side lower side air mix) connector to No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper side air mix).
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Enter the following menus: Body Electrical / Air Conditioner / Active Test.

Check the operation by referring to the table below.

Body Electrical > Air Conditioner > Active Test

Tester Display	Measurement Item	Control Range	Restrict Condition
Cool A/M Servo Pulse(D)	for LHD: No. 2 air conditioning radiator damper servo sub-assembly (driver side lower air mix) operation3 for RHD:* No. 4 air conditioning radiator damper servo sub-assembly (driver side lower air mix) operation*3	Min.: 128 Max.: 383	for LHD: Operates between 254 and 358 pulses for RHD: Operates between 154 to 258 pulses

Tester Display

Measurement Item

Control Range

Restrict Condition

Cool A/M Servo Pulse(D)

for LHD:
No. 2 air conditioning radiator damper servo sub-assembly (driver side lower air mix) operation*3

for RHD:
No. 4 air conditioning radiator damper servo sub-assembly (driver side lower air mix) operation*3

Min.: 128

Max.: 383

for LHD:
Operates between 254 and 358 pulses

for RHD:
Operates between 154 to 258 pulses

Body Electrical > Air Conditioner > Active Test

Tester Display

Cool A/M Servo Pulse(D)

Tester Display
Cool A/M Servo Pulse(D)

OK
No. 2 air conditioning radiator damper servo sub-assembly1 or No. 4 air conditioning radiator damper servo sub-assembly2 (driver side upper air mix) is operated.

Result

Proceed to
OK
NG

OK
REPLACE AIR CONDITIONING HARNESS ASSEMBLYClick here
NGClick here

Click here

CHECK AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY

Interchange the driver side upper air mix servo motor with driver side lower air mix servo motor and connect the connectors to them.

Click here
Clear the DTCs.

Click here

Check for DTCs.

Click here

Result

Result	Proceed to
DTC B1453 is output (for LHD)	A
DTC B1453 is output (for RHD)	B
DTC B1446 is output	C
DTCs are not output	D

Tip:

Codes other than DTC B1446 and B1453 may be output at this time, but they are not related to this check.

A
REPLACE NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLYClick here
B
REPLACE NO. 4 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLYClick here
C
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLYClick here
D
USE SIMULATION METHOD TO CHECKClick here

AIR CONDITIONING SYSTEM, Diagnostic DTC:B1446