Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Toyota Tacoma. However, it is still accessible from the selected car via links, so may be relevant.

Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

NOTE: It is recommended OBD monitor and drive pattern procedure is performed to monitor for DTC(s) and Readiness Monitor status first before proceeding with repair procedure. See TEST DRIVE CONFIRMATION procedure and Figure.

For diagnosis and repair procedure using Toyota Hand-held tester, see Fig 1 & Fig 2 . For diagnosis and repair procedure using OBD II scan tool, see Fig 3.

For EGR system wiring diagram, see Figure. EGR gas temperature sensor is located near EGR valve and contains Dark Gray 2-pin connector with Pink/Blue and Blue/Black wires. To locate EGR gas temperature sensor, see Figure. EGR VSV is located on bracket, near throttle body and contains Green 2-pin connector with White/Red and Red/Black wires. See Figure. When access to, or replacement of ECM is necessary, Engine Control Module (ECM) is located behind glove box. See Figure. For ECM connector terminal view, see Figure. For vacuum or EVAP hose routing, see VACUUM DIAGRAMS article. For testing of systems or components, see SYSTEM & COMPONENT TESTING - 4-CYLINDER article. For removal and installation of components, see REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Fig 1: DTC P0402 Diagnostic Procedure Using Toyota Hand-Held Tester (Steps 1-2)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: DTC P0402 Diagnostic Procedure Using Toyota Hand-Held Tester (Steps 3-5)

Fig 3: EGR System - Excessive Flow Detected Diagnosis Using OBD II Scan Tool