October 19, 2005

Title: Technical Service Bulletin from Toyota

M.I.L. “ON” DTC P0420

Models:

2001 – 2003 Sienna Van

Introduction

Under certain driving conditions, some 2001 – 2003 model year Sienna vehicles may exhibit a M.I.L. “ON” with the following DTC:

P0420 (Catalyst System Efficiency Below Threshold [Bank 1])

The Engine Control Module (ECM) (SAE term: Powertrain Control Module/PCM) logic has been modified to improve this condition. Applicable Vehicles

2001 – 2003 model year Sienna vehicles.

Warranty Information

Applicable Warranty:

This repair is covered under the Toyota Federal Emissions 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.

Repair Procedure
1.     Verify DTC P0420 with the Diagnostic Tester by referring to the Technical Information System (TIS), 2001 – 2003 model year Sienna Repair Manual: Diagnostics: Engine: Pre-Check.

2.     Replace ECM (PCM). Follow the Repair Manual ECM replacement instructions. Refer to TIS, 2001 – 2003 model year Sienna Repair Manual: Introduction: How To Troubleshoot ECU Controlled Systems: How To Use The Diagnostic Chart And Inspection Procedure.

3.     Perform the following steps to confirm that the vehicle is repaired.

A.     Reset the Readiness test by using the “Clear DTC” function on the Diagnostic Tester.

         To clear the DTC, refer to TIS, 2001 – 2003 model year Sienna Repair Manual: Diagnostics: Engine: Pre-Check.

B.     Perform Readiness Monitor Drive Patterns for Catalyst Monitor 02S type and AF Sensor type. Refer to TSB No. EG003-02, “Readiness Monitor Drive Patterns,” procedures: Catalyst Monitor (02S Type) and Catalyst Monitor (AF Sensor Type).

C.     If a DTC is set during the above drive patterns, refer to the Diagnostic Trouble Code Chart in TIS, 2001 – 2003 model year Sienna Repair Manual: Diagnostics: Engine: Diagnostic Trouble Code Chart. Test drive the vehicle to confirm normal operation.

4.     If NO DTCs (pending or current) are stored, the repair is complete.