A/C - Poor Heater Performance When Cold

T-SB-0231-10

August 5, 2010

Heater Performance
Service Category

Engine/Hybrid System
Engine Control

Market
USA





Applicability

Introduction

Some 2008 model year Sequoia and 2007 - 2008 model year Tundra vehicles may exhibit reduced cold-start heater warm-up performance in cold conditions. A newly designed Engine Control Module/ECM (SAE term: Powertrain Control Module/PCM) logic is available to address this condition. Use the following repair procedure to recalibrate the ECM (PCM).





Warranty Information

APPLICABLE WARRANTY

^ This repair is covered under the Toyota Federal Emission Warranty. This warranty is in effect for 96 months or 80,000 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.

Production Change Information





This TSB applies to vehicles produced BEFORE the Production Change Effective VINs shown.





Required Tools & Equipment











Parts Information











Calibration Information

Repair Procedure

1. Confirm the condition matches the Introduction.





2. Check for the Authorized Modifications Label affixed to the vehicle in the location shown in Figure 1. Confirm if the ECM (PCM) calibration has been updated. If the calibration ID listed is NOT the latest ECM (PCM) calibration - go to step 3.

3. Flash reprogram the ECM (PCM).

NOTE

^ The GR8 Battery Diagnostic Station MUST be used in Power Supply Mode to maintain battery voltage at 13.5 volts while flash reprogramming the vehicle.

^ For details on how to use the GR8 Battery Diagnostic Station, refer to the GR8 Instruction Manual located on the Technical Information System (TIS), Diagnostics - Battery.

Follow the procedures outlined in TSB No. T-SB-0064-10, "Techstream ECU Flash Reprogramming Procedure", and flash the ECM (PCM) with the NEW calibration file update.

4. Install the Authorized Modifications Label.

A. Using a permanent marker enter the following information on the label:

^ ECM part number [Refer to the Parts Information section for the CURRENT PART NUMBER]

^ Calibration ID(s) [Refer to the Calibration Identification Chart for the NEW CALIBRATION ID]

^ Dealer Code

^ Repair Date

^ Change Authority [This TSB number]

B. Affix the Authorized Modifications Label to the vehicle at the location shown in Figure 1. The Authorized Modifications Label is available through the MDC P/N 00451-00001-LBL.

5. Test drive the vehicle to confirm proper vehicle operation.