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2004 - 2005 Toyota Sienna ECM Calibration: Shift Feeling Enhancement


Applicable Vehicles: 2004 – 2005 model year Sienna vehicles

To improve the transmission shift feeling during specific operating modes, the Engine Control Module (ECM) (SAE term: Powertrain Control Module/PCM) calibration has been revised. These improvements include:

􀀀 Reduced downshift lag when accelerating at speeds from 10 to 20 mph.

􀀀 Less gear hunting when driving on/off accelerator pedal at 20 to 30 mph (for example: during heavy rush–hour traffic).

􀀀 Improved response rate during heavy acceleration from a stop.

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 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 calibration (see Figure 2).

– The sample screen prints seen below are the 12.1a software version and may differ from subsequent software versions.

3. If 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)

Follow the procedures outlined in Toyota TSB No. SS002–01, “ECU Flash Reprogramming Process,” and flash the ECM (PCM) with the new calibration file update. Download File PDF

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