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Home >> Chevrolet >> 2000 >> Venture Base, Van Cargo Extended >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P0480: Cooling Fan Relay No. 1 Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Turn ignition on, with engine off. Using scan tool, command cooling fan relay No. 1 on and off. If relay turns on and off, see DIAGNOSTIC AIDS . If relay does not turn on and off, go to next step.
  3. Turn ignition off. Remove relay. Turn ignition on, with engine off. Using a test light connected to ground, probe relay coil battery feed circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step  10.
  4. Connect test light between relay coil battery feed circuit and relay control circuit. Using scan tool, command relay on and off. If test light turns on and off, go to step  8. If test light does not turn on and off, go to next step.
  5. If test light remains illuminated for each command, go to step  7. If test light does not remain illuminated for each command, go to next step.
  6. Check relay control circuit for an open or short to voltage. Repair as necessary. After repairs, go to step  13. If circuit is okay, go to step  9.
  7. Check relay control circuit for short to ground. Repair as necessary. After repairs, go to step  13. If circuit is okay, go to step  9.
  8. Check for faulty relay connections. Repair as necessary. After repairs, go to step  13. If connections are okay, go to step  11.
  9. Check for faulty PCM harness connections. Repair as necessary. After repairs, go to step  13. If connections are okay, go to step  12.
  10. Repair relay coil battery feed circuit. After repairs, go to step  13.
  11. Replace relay. After replacing relay, go to step  13.
  12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  13. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, system is okay. If scan tool does not indicate that this test ran and passed, go to step  2.
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