LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chevrolet >> 2003 >> Tracker 4D Utility, 2.5 4, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel Systems >> Main Relay Circuit Diagnosis (2.5L) >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

  1. Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in SELF-DIAGNOSTICS - 2.5L TRACKER article. After performing diagnostic 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 clicking sound from relay. If relay clicks, go to next step. If relay does not click, go to step  5.
  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 No. 1. See Figure. If test light illuminates, go to step  14. 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 No. 3. See Figure. 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 No. 5. 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  17.
  8. Check for open in main relay control circuit between main relay and PCM. Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  9. Using test light connected to ground, backprobe PCM harness connector C4 terminal No. 3 (ignition feed circuit). See Fig 1. 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 harness connector C4 terminal No. 3. After repairs, go to step  17.
  11. Disconnect 26-pin PCM harness connector C2 and 28-pin PCM harness connector C4. See Fig 1 and Fig 2 . Using test light connected to battery positive, probe PCM ground circuits at PCM harness connector C2 terminals No. 25 (Black/Green wire) and No. 26 (Black/Blue wire), and PCM harness connector C4 terminals No. 2 (Black/Orange wire), No. 8 (Black/Green wire) and No. 9 (Black/Blue wire). If test light illuminates for all circuits, go to step  16. If test light does not illuminate for all circuits, go to next step.
  12. Repair any open PCM ground circuit(s). After repairs, go to step  17.
  13. Repair short to ground in FI fuse circuit or IG fuse circuit. After repairs, go to step  17.
  14. Check main relay circuit for an open or a poor connection from main relay terminal No. 2, to component or system that is not receiving voltage. Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  15. Replace main relay. After repairs, go to step  17.
  16. Replace PCM. See REMOVAL & INSTALLATION - TRACKER article. After repairs, go to next step.
  17. 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 DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate SELF-DIAGNOSTICS article.
Fig 1: Identifying PCM Harness Connector C4 Terminals (Back View)
G00117322Courtesy of GENERAL MOTORS CORP.
Fig 2: Identifying PCM Harness Connector C2 Terminals (Back View)
G00117320Courtesy of GENERAL MOTORS CORP.
scientia non olet · About LEMON Manuals