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Home >> Chevrolet >> 2000 >> Tracker 4D Utility, RWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures >> Basic Fuel System Checks >> Main Relay Circuit Diagnosis >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform OBD system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
  2. Check condition of FI fuse (15-amp) located in fuse block at right side of engine compartment, and IG fuse (20-amp) located in junction block. If either fuse is open, go to step  13 . If fuses are okay, go to next step.
  3. Turn ignition on. Remove, and then reinstall main relay several times while listening for relay operation. If relay operates, see DIAGNOSTIC AIDS  . If relay does not operate, go to next step.
  4. Turn ignition off. Remove main relay. Turn ignition on. Using test light connected to ground, probe main relay battery feed circuit (relay switch power) at relay cavity. If test light illuminates, go to next step. If test light does not illuminate, go to step  7 .
  5. Using test light connected to ground, probe main relay battery feed circuit (relay coil power) at relay cavity. If test light illuminates, go to next step. If test light does not illuminate, go to step  7 .
  6. Turn ignition off. Using test light connected to battery positive, probe main relay control circuit at relay cavity. Turn ignition on. If test light illuminates, go to step  14 . If test light does not illuminate, go to step  8 .
  7. Repair open in battery feed circuit between main relay and FI fuse. After repairs, go to step  16 .
  8. Check for open in main relay control circuit between main relay and PCM. Repair as necessary. After repairs, go to step  16 . If circuit is okay, go to next step.
  9. Using test light connected to ground, backprobe terminal No. 20 (ignition feed circuit) at PCM harness connector. If test light illuminates, go to step  11 . If test light does not illuminate, go to next step.
  10. Repair open in ignition feed circuit between IG fuse and PCM. After repairs, go to step  16 .
  11. Disconnect 26-pin and 30-pin PCM harness connectors. Using test light connected to battery positive, probe PCM ground circuits (Black/Blue wires and Black/Green wire) at PCM harness connectors. If test light illuminates for all circuits, go to step  15 . If test light does not illuminate for all circuits, go to next step.
  12. Repair open in PCM ground circuit(s). After repairs, go to step  16 .
  13. Repair short to ground in FI fuse circuit or IG fuse circuit. After repairs, go to step  16 .
  14. Replace main relay. After repairs, go to step  16 .
  15. Replace PCM. Perform PCM relearn procedures. After repairs, go to next step.
  16. Operate vehicle under conditions which original symptom was noted. If system operates properly with no DTCs set, system is okay. If DTCs are set, diagnose using appropriate diagnostic procedure for DTC set. See appropriate SELF-DIAGNOSTICS article.
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