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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 133 (Multiplex Communication System) >> Diagnostic Tests >> DTC B1269: Theft Deterrent Ecu Communication Stopped >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Lexus ES 300 and 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition off. Disconnect body ECU 18-pin harness connector B5 and theft deterrent ECU 26-pin harness connector T6. See Figure. Backprobing, check continuity of Violet wire between body ECU 18-pin harness connector B5 terminal No. 13 (MPX3 circuit) and theft deterrent ECU 26-pin harness connector T6 terminal No. 10 (MPX1 circuit). See Figure and Fig 1 . If continuity exists, go to next step. If continuity does not exist, repair Violet wire, harness or connector between body ECU and theft deterrent ECU and retest system. See COMPUTER DATA LINES in SYSTEM WIRING DIAGRAMS article.
  2. With theft deterrent ECU 26-pin harness connector T6 disconnected, check power feed circuit (+B1) by backprobing between harness side of connector T6 terminal No. 2 (White/Red wire) and good body ground point. See Fig 2. If 10-14 volts is present, go to next step. If 10-14 volts is not present, repair White/Red wire, harness, connector or fuse(s) between theft deterrent ECU and battery. See Fig 1.
  3. With theft deterrent ECU 26-pin harness connector T6 disconnected, check ground circuit ("E") by backprobing between harness side of connector T6 terminal No. 11 (White/Black wire) and good body ground point. See Fig 3. If continuity does not exist, repair White/Black wire, harness or connector between theft deterrent ECU and vehicle ground point located on instrument panel reinforcement under left side of instrument panel. See Fig 1. If continuity exists, replace theft deterrent ECU. See THEFT DETERRENT ECU (SECURITY ECU)  under REMOVAL & INSTALLATION.
  4. After repairs have been made, perform confirmation test. See CONFIRMATION TEST  under SELF-DIAGNOSTIC SYSTEM.
Fig 1: Theft Deterrent ECU Wiring Diagram
G00173719Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Testing Theft Deterrent ECU Power Feed Circuit
G00173721Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 3: Testing Theft Deterrent ECU Ground Circuit
G00173722Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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