Toyota 4Runner: Air Inlet Damper Control Servo Motor Circuit (B1442)

Toyota 4Runner Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System(for Manual Air Conditioning System) / Air Inlet Damper Control Servo Motor Circuit (B1442)

DESCRIPTION

The recirculation damper servo sub-assembly sends pulse signals to inform the No. 1 air conditioning amplifier assembly of the damper position. The No. 1 air conditioning amplifier assembly activates the motor (normal or reverse) based on the signals to move the air inlet damper to any position, which controls the intake air settings (fresh, fresh/recirculation and recirculation).

HINT:

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

DTC Code	DTC Detection Condition	Trouble Area
B1442	The air inlet damper position does not change when the air conditioning amplifier assembly operates the recirculation damper servo sub-assembly.	Recirculation damper servo sub-assembly Air conditioning harness assembly No. 1 air conditioning amplifier assembly

WIRING DIAGRAM

PROCEDURE

1.	READ VALUE USING TECHSTREAM (RECIRCULATION DAMPER SERVO)

(a) Use the Data List to check if the recirculation damper servo sub-assembly is functioning properly (See page ).

Air Conditioner

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Air Inlet Damper Targ Pulse	Recirculation damper servo sub-assembly target pulse / Min.: 0, Max.: 255	7 (pulse): Recirculation 28 (pulse): Fresh	-
Air Inlet Damper Actual Pulse	Recirculation damper servo sub-assembly actual pulse / Min.: 0, Max.: 255	7 (pulse): Recirculation 28 (pulse): Fresh	-

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Air Inlet Damper Targ Pulse

Recirculation damper servo sub-assembly target pulse / Min.: 0, Max.: 255

7 (pulse): Recirculation

28 (pulse): Fresh

Air Inlet Damper Actual Pulse

Recirculation damper servo sub-assembly actual pulse / Min.: 0, Max.: 255

7 (pulse): Recirculation

28 (pulse): Fresh

OK:

The display is as specified in the normal condition column.

Result

Result	Proceed to
OK (When troubleshooting according to problem symptoms table)	A
OK (When troubleshooting according to the DTC)	B
NG	C

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY

2.	PERFORM ACTIVE TEST USING TECHSTREAM (RECIRCULATION DAMPER SERVO)

(a) Select the Active Test, use the Techstream to generate a control command, and then check that the recirculation damper servo sub-assembly operates (See page ).

Air Conditioner

Tester Display	Test Part	Control Range	Diagnostic Note
Air Inlet Damper Targ Pulse	Recirculation damper servo sub-assembly target pulse	Min.: 0, Max.: 255	-

OK:

Recirculation damper servo sub-assembly operates normally.

REPLACE NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY

3.	REPLACE RECIRCULATION DAMPER SERVO SUB-ASSEMBLY

(a) Replace the recirculation damper servo sub-assembly (See page ).

HINT:

Since the recirculation damper servo sub-assembly cannot be inspected while it is removed from the vehicle, replace the recirculation damper servo sub-assembly with a new or normally functioning one.

4.	CHECK FOR DTC

(a) Clear the DTCs (See page ).

(b) Check for DTCs (See page ).

OK:

DTC B1442 is not output.

END (RECIRCULATION DAMPER SERVO SUB-ASSEMBLY IS FAULTY)

5.	REPLACE NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Temporarily replace the No. 1 air conditioning amplifier assembly with a new or normally functioning one (See page ).

6.	CHECK FOR DTC

(a) Clear the DTCs (See page ).

(b) Check for DTCs (See page ).

OK:

DTC B1442 is not output.

END (NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY IS FAULTY)

REPLACE AIR CONDITIONING HARNESS ASSEMBLY

Communication Malfunction (Bus Ic) (B1497)

DESCRIPTION The air conditioning harness assembly connects the No. 1 air conditioning amplifier assembly and each servo motor. The No. 1 air conditioning amplifier assembly supplies power and sen ...

Evaporator Temperature Sensor Circuit (B1413)

DESCRIPTION The No. 1 cooler thermistor is installed on the evaporator in the air conditioning unit to detect the temperature of the cooled air that has passed through the evaporator and control ...

Other materials about Toyota 4Runner:

Inspection
INSPECTION PROCEDURE 1. INSPECT TRANSMISSION CONTROL SWITCH (a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition ...

ECU Circuit (61)
DESCRIPTION When the internal circuit of the side auto step controller ECU assembly malfunctions, the side auto step controller ECU assembly halts the operation of the system. DTC No. DTC Detection Condition Trouble Area ...