A/C - Warm Air From Vents/DTC B1479 Set
T-SB-0053-11June 2, 2011
Warm Air from HVAC Vents with A/C ON - DTC B1479
Service Category
Vehicle Interior
Section
Heating/Air Conditioning
Market
USA
Applicability
Introduction
Some Sienna vehicles may exhibit a condition where the HVAC system intermittently blows warm air from the vents with the A/C on.
When this condition occurs Diagnostic Trouble Code (DTC) B1479 (Flow Sensor Circuit) may also be stored in the A/C system as either a Current or History DTC. A malfunctioning A/C compressor flow sensor may cause this condition.
Follow the procedure in this TSB to determine if this service bulletin is applicable and to repair the vehicle.
Production Change Information
This TSB applies to vehicles produced BEFORE the Production Change Effective VINs shown.
Parts Information
Warranty Information
Required Tools & Equipment
Repair Procedure
1. Using TIS Techstream check for Diagnostic Trouble Codes (DTCs) in the A/C system.
^ If DTC B1479 is stored as a Current or History DTC go to step 2.
^ If DTC B1479 is NOT stored as Current or History this TSB does NOT apply. Refer to the problem symptoms table of the Repair Manual.
Refer to the Technical Information System (TIS) 2011 Sienna Repair Manual:
Vehicle Interior - Heating/Air Conditioning - "Heating/Air Conditioning: Air Conditioning: Air Conditioning System (for Manual Air Conditioning System) / (for Automatic Air Conditioning System): Problem Symptoms Table"
2. Using Techstream inspect the flow sensor.
A. Connect Techstream to the DLC3.
B. Enter the following menus:
Body Electrical / Air Conditioner / Data List
C. Check the flow sensor voltage.
(1) With the A/C OFF and the voltage reading is LESS than 3.7 V continue to step 3.
(2) With the A/C ON and the voltage reading is MORE than 3.7 V evacuate the A/C system and verify refrigerant charge level.
^ If the system is under charged recharge and see if DTC B1479 sets again.
^ If the system is fully charged continue to step 3.
3. Check the harness and connector (A/C compressor flow sensor - A/C amplifier).
A. Disconnect the flow sensor connector.
B. Disconnect the air conditioning amplifier connector.
C. Measure the resistance according to the value(s) in the table.
^ If any of the harness resistance tests fail this TSB does NOT apply. Repair or replace the harness and go to step 5.
^ If all harness tests are within specifications proceed to step 4.
4. Remove and replace the A/C compressor.
Refer to TIS 2011 model year Sienna Repair Manual:
Vehicle Interior - Heating/Air Conditioning - "Heating/Air Conditioning: Compressor (for 1AR-FE) / (for 2GR-FE): Removal"
Vehicle Interior - Heating/Air Conditioning - "Heating/Air Conditioning: Compressor (for 1AR-FE) / (for 2GR-FE): Installation"
5. Clear all DTCs and confirm the A/C system has returned to proper operation.