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Circuit Test NN

  1. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect Throttle Position Sensor (TPS). Turn key on, leaving engine off. Measure voltage between VREF circuit at TPS harness connector and signal return circuit in SELF-TEST connector. If reading is less than 4 volts or more than 6 volts, go to CIRCUIT TEST C  , step 1). If reading is between 4 and 6 volts, connect TPS and go to next step.
  2. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 48 and Self-Test Input (STI) at SELF-TEST connector pigtail. If reading is 5 ohms or more, repair open in circuit. If reading is less than 5 ohms, go to next step.
  3. With breakout box installed and DVOM on 200 ohm scale, measure resistance between test pin No. 17 and Self-Test Output (STO) at SELF-TEST connector. If reading is 5 ohms or more, repair open in circuit. If reading is less than 5 ohms, go to next step.
  4. Turn key off. With breakout box installed and DVOM on 200 ohm scale, measure resistance between test pin No. 29 and EGO sensor engine block ground. If reading is 5 ohms or more, repair EGO sensor ground wire or open circuit bad connection. If reading is less than 5 ohms, go to next step.
  5. With breakout box installed and DVOM on 200 ohm scale, measure resistance between STO at SELF-TEST connector and engine block ground. If reading is more than 5 ohms, replace ECA and repeat QUICK TEST  . If reading is less than 5 ohms, go to step 8).
  6. Turn key off. Leave breakout box installed and ECA disconnected. Disconnect HEGO sensor and set DVOM on 200,000 ohm scale. Measure resistance between test pin No. 29 and test pins No. 37 and 57. If reading is less than 10,000 ohms, go to next step. If reading is not less than 10,000 ohms, repair harness short to power. Repeat QUICK TEST  .
  7. Leave key off, DVOM on 200,000 ohm scale, and HEGO sensor disconnected. Measure resistance between RUN circuit and EGO circuit at HEGO connector. If reading is less than 10,000 ohms, replace HEGO and repeat QUICK TEST  . If reading is not less than 10,000 ohms, go to next step.
  8. Leave key off and breakout box installed. Set DVOM on 20 volt scale. Connect DVOM to test pin No. 30 and test pins No. 40 or 60. Perform ENGINE RUNNING SELF-TEST. If reading is greater than 1 volt, repair intermittent fault in NDS harness connector or switch. If okay, go to ENGINE RUNNING SELF-TEST for appropriate service codes. If reading is not greater than one volt, repair intermittent fault in NDS harness connector or switch. If okay, go to next step.
  9. Leave key off and breakout box installed. Set DVOM on 20 volt scale. Connect DVOM to test pins No. 37 or 57 and test pins No. 40 or 60. Turn key on, then off. Wait 10 seconds. If reading does not changes from 10.5 volts (or higher) to zero volts, replace EEC power relay or Integral Relay Control Module (IRCM). Repeat QUICK TEST  . If reading changes from 10.5 volts (or higher) to zero volts, go to next step.
  10. If vehicle is not equipped with shift indicator light, repair Self-Test Output (STO) circuit for short to ground. Repeat QUICK TEST  . If vehicle is equipped with shift indicator light, go to next step.
  11. Continuous Code 15 Displayed. Clear continuous memory codes using procedure described in CONTINUOUS SELF-TEST. Repeat KEY ON/ENGINE OFF SELF-TEST through continuous memory code output. If continuous code 15 is not displayed, continuous code 15 testing is complete. If continuous code 15 is displayed, go to next step.
    NOTE: Continuous code 15 is displayed when power to Keep Alive Memory (KAM), test pin No. 1 at ECA is interrupted. Code 15 may also be displayed the first time SELF-TEST is performed and power is restored to ECA. Repeat SELF-TEST to ensure correct diagnosis.
  12. Ensure that EEC-IV components and wiring are not close to high tension secondary voltage wires or ignition components. If EEC-IV wiring is close to high tension wires, reroute EEC wiring and repeat QUICK TEST  . If continuous code 15 is no longer displayed, continuous code 15 testing is complete. If continuous code 15 is still displayed, go to next step.
  13. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Connect DVOM positive test lead to test pin No. 1 and negative test lead to pins No. 40 or 60. Turn key on and observe voltage reading. If reading is less than 10 volts, repair open to KAM circuit. Repeat QUICK TEST  . If reading is 10 volts or greater, replace ECA and repeat QUICK TEST  .
  14. Check or perform diagnosis of non-EEC related areas. Check all areas that may contribute to a particular condition in order of probability, ease of accomplishment, and accessibility. Use your technical knowledge and experience to determine which areas may be the source of problem before starting a more involved diagnosis. After correcting faults, go to next step.
  15. Turn key off and wait 10 seconds. Install tachometer. Start engine and attempt to maintain engine at 2000 RPM for 2 minutes. If 2000 RPM can be maintained, go to CIRCUIT TEST A  , step 13). If 2000 RPM cannot be maintained, go to next step.
  16. With engine at operating temperature and tachometer installed, turn key off and wait 10 seconds. Perform ENGINE RUNNING SELF-TEST while maintaining engine at 2000 RPM. If code 11 (Pass) is displayed, go to ENGINE RUNNING SELF-TEST. If any other service code is displayed, go to ENGINE RUNNING SELF-TEST table and service code(s) as instructed. If no codes are displayed, go to step 1).
  17. Output State Check Not Functioning. Turn key off and wait 10 seconds. Perform KEY ON/ENGINE OFF SELF-TEST and leave key on to enter OUTPUT STATE CHECK. If codes 23, 53, 63 or 68 are displayed, go to KEY ON/ENGINE OFF SELF-TEST table and service code(s) as instructed. If no codes are displayed, go to step 1). If code 11 (Pass) is displayed, go to next step.
  18. Check throttle and linkage for sticking or binding. If throttle and linkage are okay, replace TPS and repeat QUICK TEST  . If throttle and linkage are binding, repair as necessary and repeat QUICK TEST  .
  19. Power To ECA Check. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between test pins No. 37 and 40, and between test pins No. 57 and 60. If either reading is less than 10.5 volts, go to CIRCUIT TEST B  , step 1) for all others. If both readings are 10.5 volts or more, replace ECA and repeat QUICK TEST  .
Fig 1: No Codes/Codes Not Listed Circuits
G48122
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