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Starter Signal Circuit: Tundra

  1. If using Toyota hand-held tester, go to next step. If Toyota hand-held tester is not available, go to step  5.
  2. Connect hand-held tester to data link connector No. 3. See Figure. Turn ignition on and then turn hand-held tester on. Read STA signal display on hand-held tester with ignition on and with ignition switch in START position and engine cranking. The STA signal display should read OFF with ignition on and ON with ignition switch in START position. If STA signal display is not as specified, go to next step. If STA signal display is as specified, diagnose by symptom. See TROUBLE SHOOTING - NO CODES article.
  3. Check for open and short in Black/White wire and electrical connectors between starter relay and starter fuse, defective starter fuse, and for open and short in Black wire and electrical connectors between starter fuse and terminal No. 7 at Engine Control Module (ECM) electrical connector E3 on V6 models or electrical connector E4 on V8 models. This is the starter signal circuit between starter relay and ECM. See WIRING DIAGRAMS article. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, next to battery. Starter fuse is located in fuse box behind driver's side of instrument panel. Starter fuse may be marked as STA fuse. ECM is located behind glove box and heater duct. For illustration of ECM location, see THEORY & OPERATION article. For ECM electrical connector terminal identification, see Figure and Figure .
  4. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
  5. Remove glove box and heater duct for access to Engine Control Module (ECM). For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminals. See Figure and Figure .
  6. Using voltmeter, check voltage between body ground and terminal No. 7 (Black wire) at ECM electrical connector E3 on V6 models or electrical connector E4 on V8 models with ignition switch in START position and engine cranking. This is the STA terminal at ECM. Voltage should be 6 volts or more. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See TROUBLE SHOOTING - NO CODES article.
  7. Check for open and short in Black/White wire and electrical connectors between starter relay and starter fuse, defective starter fuse, and for open and short in Black wire and electrical connectors between starter fuse and terminal No. 7 at ECM electrical connector E3 on V6 models or electrical connector E4 on V8 models. See WIRING DIAGRAMS article. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, next to battery. Starter fuse is located in fuse box behind driver's side of instrument panel. Starter fuse may be marked as STA fuse.
  8. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
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