Engine Controls - Idle Hunting in Sub-Freezing Temp

ENGINE
EG022-07

Title:
"IDLE HUNTING" IN SUB-FREEZING
AMBIENT AIR TEMPERATURES

Models:
'03-'04 Corolla & Matrix (MTM)

April 18, 2007

Introduction

Some 2003 - 2004 model year Corolla and Matrix vehicles may exhibit an "idle hunting" condition after the vehicle has been cold soaked in sub-freezing ambient air temperatures. During this condition the engine idle will "hunt" or fluctuate instead of maintaining a constant fast idle speed. The Engine Control Module (ECM) (SAE term: Powertrain Control Module/PCM) logic has been modified to correct this condition.

Applicable Vehicles

^ 2003 - 2004 model year Corolla and Matrix (2WD) vehicles equipped with manual transmission.





Parts Information





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 correction of a problem based upon a customer's specific complaint.





Required SSTs





Calibration Identification Chart

Repair Procedure





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





2. Connect the Diagnostic Tester to the vehicle and select CURRENT ECU CAL from the ECU REPROGRAM MAIN MENU. Determine the vehicle's current ECU calibrations (see Figure 2).

- The sample screen prints seen below are the 14.1 a software version and may differ from subsequent software versions.

NOTE:
^ If the Calibration ID matches the "Previous Calibration ID" as shown in the Calibration Identification Chart in this TSB, proceed with flash reprogramming.

^ If the Calibration ID matches the "New Calibration ID" as shown in the Calibration Identification Chart, this vehicle has already been programmed. Refer to the Technical Information System (TIS) for diagnostic procedures applicable to any stored DTCs.

3. If the ECU calibration ID is NOT the same as the New Calibration ID" listed previously, proceed to Flash Reprogram ECM (PCM).

4. Flash Reprogram ECM (PCM)

NOTE:

^ The GR8 Battery charger 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 charger please refer to the GR8 Instructions Manual, located on TIS, Diagnostics - Battery.

Follow the procedures outlined in TSB No. SS002-01, "ECU Flash Reprogramming Process, " and flash the ECM (PCM) with the NEW calibration file update.

NOTE:
If the "Check Engine" light is ON when the ignition is turned back ON to begin the reprogramming process, a scan tool cable problem exists. Refer to TSB No. SS004-01, "ECU Flash Reprogramming Error Message."

5. Install the Authorized Modifications Label.

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

^ ECM (PCM) 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): EG022-07

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.

6. Start the engine and warm it up to normal operating temperature before test-driving.

7. Test-drive vehicle to confirm proper vehicle operation.

8. Calibration update is complete.