Last Modified: 11-29-2007 1.6 C
Service Category: Vehicle Interior Section: Heating/Air Conditioning
Model Year: 2008 Model: Sequoia Doc ID: RM000002VXK004X
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DESCRIPTION (2008 Sequoia)

DTC

B1446/46

Air Mix Damper Control Servo Motor Circuit (Driver Side)

DESCRIPTION

The air mix damper servo (for driver side) sends pulse signals to inform the air conditioning amplifier of the damper position. The air conditioning amplifier activates the motor (normal, reverse) based on the signals to move the air mix damper (for driver side) to any position. As a result, the amount of air that has passed through the evaporator and is now passing through the heater core is adjusted, and the temperature of the air blowing toward the driver side is controlled.

HINT:

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

DTC Code

DTC Detection Condition

Trouble Area

B1446/46

Air mix damper position sensor value does not change even if air conditioning amplifier operates air mix servo motor
  • Cooling unit damper servo sub-assembly (Air mix damper servo (for driver side))
  • Air conditioning harness
  • Air conditioning amplifier

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

READ VALUE USING TECHSTREAM (AIR MIX SERVO TARG PULSE (D))

(a) Connect the Techstream to DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List / Air Mix Servo Targ Pulse (D).

(e) According to the display on the Techstream, read the Data List.

Air Conditioner

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Air Mix Servo Targ Pulse (D)

Driver side air mix servo motor target pulse /

Min.: 0

Max.: 255

Customized value will be displayed

-

OK:

The display is as specified in the normal condition.

Result

Result

Proceed to

NG

A

OK (When troubleshooting according to Problem Symptoms Table)

B

OK (When troubleshooting according to the DTC output)

C
A

4.

REPLACE COOLING UNIT DAMPER SERVO SUB-ASSEMBLY (AIR MIX DAMPER SERVO (for Driver Side))

(a) Temporarily replace the cooling unit damper servo sub-assembly (air mix damper servo) with a new one HEATING / AIR CONDITIONING: FRONT AIR CONDITIONING UNIT: DISASSEMBLY (2008 Sequoia) .

HINT:

Since the damper servo cannot be inspected while it is removed from the vehicle, replace the damper servo with a new one and check that the condition returns to normal.

NEXT

5.

CHECK FOR DTC

(a) Clear the DTC HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DTC CHECK / CLEAR (2008 Sequoia) .

(b) Check for DTC HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DTC CHECK / CLEAR (2008 Sequoia) .

OK:

DTC is not output.

OK

7.

REPAIR OR REPLACE AIR CONDITIONING HARNESS

(a) Repair or replace the air conditioning harness HEATING / AIR CONDITIONING: FRONT AIR CONDITIONING UNIT: DISASSEMBLY (2008 Sequoia) .

NEXT

8.

CHECK FOR DTC

(a) Clear the DTC HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DTC CHECK / CLEAR (2008 Sequoia) .

(b) Check for DTC again HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DTC CHECK / CLEAR (2008 Sequoia) .

OK:

DTC is not output.

OK