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Computer Test

  1. If there is continuity after step 17) or 14, check computer. Disconnect computer and inspect connector on harness side. Turn main switch on. 12 volts should exist between terminal 7 (Celica, Cressida, Corolla and Supra) or 10 (Pickup, 4Runner and Van ) and ground. If not, check for open in harness between terminal 7 or 10 (as applicable) of computer and terminal 1 (Celica, Corolla and Supra), 7 (Pickup & 4Runner) or 2 (Van and Cressida) of main switch.
  2. If continuity existed in step 1) inspect ground connection. Continuity should exist between terminal 10 (Celica, Corolla, Cressida and Supra), 13 (Pickup, 4Runner and Van) and ground. If not, check for open in harness between applicable terminal and ground.
  3. If continuity existed in step 2), inspect "SET/COAST" switch circuit. Turn "SET/COAST" switch on and check for continuity between terminal 4 (Celica, Corolla, Cressida and Supra), 5 (Pickup & 4Runner) or 17 (Van) and ground. If none, check for open between terminal 4, 5 or 17 (as applicable) of computer and terminal 25 (Celica), 30 (Supra), 5 (Corolla RWD), 24 (Corolla FWD, Cressida and Pickup & 4Runner) or 1 (Van) of control switch. Inspect control switch.
  4. If continuity existed in step 3), turn "SET/COAST" switch off and check for continuity between terminal 4 (Celica, Cressida, Corolla and Supra), 5 (Pickup & 4Runner) or 17 (Van) and ground. If continuity exists, check for short in harness between terminal 4, 5 or 17 (as applicable) and terminal 24 (Celica, Corolla FWD, Cressida, Supra, Pickup and 4Runner), 5 (Corolla RWD) or 1 (Van) of control switch. Inspect control switch.
  5. If no continuity existed in step 4), check "ACCEL/RESUME" switch circuit by turning switch on and checking for continuity between terminal 13 (Celica, Corolla, Cressida and Supra) or 16 (Pickup, 4Runner and Van) and ground. If no continuity exists, check for a short in harness between terminal 13 or 16 (as applicable) of computer and terminal 23 (Celica, Cressida, Corolla FWD, 4Runner and Pickup), 28 (Supra) or 2 (Corolla RWD and Van) and control switch. Inspect switch.
  6. There should be no continuity in step 5) with the "ACCEL/RESUME" switch off. If continuity, check for a short in harness between terminal 13 or 16 (as applicable) of computer and terminal 23 (Celica, Cressida, Corolla FWD, Supra, 4Runner and Pickup) or 2 (Van and Corolla RWD) of control switch.
  7. If checking Celica, Corolla, Cressida, Supra, 4Runner or Pickup, inspect control valve circuit by going to step 12) or 13. For Van, if no continuity existed in step 6) with the "ACCEL/RESUME" switch off, inspect the actuator motor circuit for continuity between computer terminals 2 and 4. If there is no continuity, check for a severed wire between computer terminals 2 and 4 and actuator terminals 1 and 6 respectively. Inspect actuator.
  8. If there was continuity in step 7), inspect potentiometer circuit for 2000 ohms resistance between computer terminals 1 and 3. If none, check for severed wire or short between computer terminals 3 and 1 and actuator terminals 3 and 4 respectively. Check actuator.
  9. If there was correct resistance in step 8), check for continuity between computer terminals 6 and 3. If none, check for severed wire or short between computer terminal 6 and actuator terminal 2.
  10. If there was continuity in step 9), disconnect actuator connector and check for ground between computer terminal 3 and body ground. If yes, there is a short in wire between computer and actuator terminals 3. If no ground, check for ground between computer terminal 6 and ground. If yes, there is a short in wire between computer terminal 6 and actuator terminal 2.
  11. If there was no ground between terminal 6 and ground, check for ground between computer terminal 1 and body ground. If yes, check for short in wire between computer terminal 1 and actuator terminal 4.
  12. Inspect control valve circuit. There should be a resistance value of about 68 ohms between terminals 2 and 3 (Corollas, Celica, Supra and Cressida). If not, there is an open between terminal 3 of computer and 2 of actuator or an open in circuit in harness between terminal 1 of actuator and 2 of computer. Inspect actuator.
  13. For Pickup and 4Runner, inspect control valve circuit by testing for 68 ohms between terminals 4 and 17. If not okay, there is an open or short in harness between terminal 4 of computer and 2 of actuator or an open between terminal 1 of actuator and 17 of computer.
  14. If step 12) was okay, for Celica, Corolla, Cressida and Supra only, inspect release valve circuit for about 30 ohms between terminals 1 and 2 with the brake pedal returned. If not right, check for open or short in harness between terminal 1 of computer and 3 of actuator and between 1 of actuator and 2 of computer. Inspect stop light switch.
  15. For Pickup and 4Runner only, if step 13) was okay, inspect release valve circuit for about 71 ohms between terminal 2 and 17 with brake pedal returned. If not right, check for open or short in harness between terminal 17 of computer and 1 of actuator, and open between terminal 2 of computer and 1 of stop light switch. Inspect switch and actuator.
  16. If yes after the last 3 steps, use this step or step 17), as applicable. For manual transmission on Celica, Cressida, Corolla and Supra, check for continuity between terminal 11 and body ground. For others, use terminal 14. Clutch pedal must be returned. If continuity exists, there is a short in harness between terminal 11 or 14 (as applicable) of computer and 3 (Celica, Cressida, Corolla FWD, Supra, 4Runner and Pickup), or 2 (Corolla RWD and Van).
  17. For automatic transmission, check for 12 volts between terminal 11 (Celica, Cressida, Corolla and Supra) or 14 (others) and body ground when shifting except to "N" position. If yes, (all except Van) there is a short in harness between terminal 11 (Celica, Cressida, Corolla and Supra) or 14 (Pickup & 4Runner) of computer and terminal 3 (Celica, Cressida and Supra), 1 (Pickup, 4Runner and Corolla FWD) or 4 (Corolla RWD) of neutral start switch. Inspect switch.
  18. For Van auto. trans. only, if, after checking for 12 volts between terminal 14 and body ground, there are not 12 volts, there is a short in wire harness between terminal 14 of computer and 2 of neutral start switch.
  19. For all, inspect parking brake switch. For all but Vans, 12 volts must not have existed in step 17), or no continuity must have existed in step 16). Return parking brake lever and check for 12 volts between terminal 15 (Van, Pickup and 4Runner) or 12 (others) and ground. If incorrect, there is short in harness between terminal 15 or 12 (as applicable) of computer and parking brake switch.
  20. If 12 volts existed between terminal 15 or 12 and ground in step 17), inspect speed sensor circuit. Disconnect connector from combination meter and check for continuity between terminal 2 (Van), 20 (Corolla FWD), 18 (Corolla RWD), 30 (Cressida), 23 (Celica and Supra) or 16 (Pickup & 4Runner) of the harness side of connector and terminal 7 (Van, Pickup and 4Runner), or 6 (Celica, Cressida, Corolla and Supra) of computer. If no continuity exists, find open in circuit.
  21. If continuity exists in step 19), check for continuity between terminal 2 (Van), 6 (Celica, Cressida, Corolla and Supra) or 7 (Pickup & 4Runner) and ground. If yes, there is a short in harness between that terminal and terminal 23 (Celica), 20 (Supra and Corolla FWD), 30 (Cressida), 18 (Corolla RWD) or 16 (Pickup & 4Runner) of combination meter. For Van, there is a short if NO continuity exists.
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