A/C - Warm Air From Vents With A/C ON/DTC B1479
L-SB-0177-09November 25, 2009
Warm Air from HVAC Vents with A/C ON - DTC B1479
Service Category
Vehicle Interior
Section
Heating/Air Conditioning
Market
USA
Applicability
Introduction
Some RX 350 vehicles may exhibit a condition where the HVAC system intermittently blows warm air from the vents with the A/C on.
Diagnostic Trouble Code (DTC) B1479 (Flow Sensor Circuit) may 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 TSIB to determine if this service bulletin is applicable and to repair the vehicle.
Production Change Information
This TSIB applies to vehicles produced BEFORE the Production Change Effective VINs shown.
Parts Information
Warranty Information
APPLICABLE WARRANTY
^ This repair is covered under the Lexus Comprehensive Warranty. This warranty is in effect for 48 months or 50,000 miles, whichever occurs first, from the vehicle's in-service date.
^ Warranty application is limited to occurrence of the specified condition described in this bulletin.
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 TSIB does NOT apply. Refer to the problem symptoms table of the Repair Manual.
Refer to the Technical Information System (TIS) 2010 model year RX 350 Repair Manual: Vehicle Interior - Heating/Air Conditioning - "Air Conditioning System/Problem Symptoms Table (to 8/2009)* / (from 8/2009)**
* Japan production vehicles (JTJ)
** NAP vehicles (2T)
2. Using Techstream inspect the flow sensor.
NOTE
The A/C system will store DTC B1479 when a voltage value between 0.7 and 4.2 V is displayed continuously for more than 8.0 minutes.
^ If the flow sensor value does NOT change when switching the A/C system/blower ON and OFF and is stuck between 0.7 and 4.0 V go to step 4.
^ If the flow sensor voltage is normal go to step 3 (wire harness check).
3. Check the harness and connector (A/C compressor flow sensor - A/C amplifier).
A. Disconnect the A/C amplifier connector.
B. Measure the resistance according to the value(s) in the table.
^ If any of the harness resistance tests fail this TSIB does NOT apply. Repair or replace the harness and go to step 5.
^ If all tests are within specifications proceed to step 4.
4. Remove and replace the A/C compressor.
Refer to TIS 2010 model year RX 350 Repair Manual:
^ Vehicle Interior - Heating/Air Conditioning - "Heating/Air Conditioning: Compressor: Removal (to 8/2009)* / (from 8/2009)**
^ Vehicle Interior - Heating/Air Conditioning - "Heating/Air Conditioning: Compressor: Installation (8/2009)* / (from 8/2009)**
* Japan production vehicles (JTJ)
** NAP vehicles (2T)
5. Clear all DTCs and confirm the A/C system has returned to proper operation.