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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 130 (Engine Control System Self Diagnostics) >> Diagnostic Tests >> DTC P1645: Multiplex Communication Malfunction >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Toyota MR2. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

Check bus communication circuits (MPX1 and MPX2) between ECM and instrument cluster and repair as necessary. For ECM location, see Figure. For ECM connector terminal view, see Figure. For circuit wiring diagram, see Fig 1. Check instrument cluster operation and repair as necessary. See appropriate GAUGES & INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If combination meter is OK, check and replace ECM.

Fig 1: Multiplex Communication Bus Circuit Wiring Diagram
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