LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1677 (Engine Cooling System) >> Diagnostic Information and Procedures >> DTC P0480 or P0481 >> Test Description

Test Description

WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2. Listen for an audible click when the cooling fan 1 relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3. Listen for an audible click when the cooling fan 2 and the cooling fan 3 relays operate. Command both the ON and OFF states. Repeat the commands as necessary.
  3. 4. Tests for voltage at the coil side of the cooling fan 1 relay. The cool fan 1 fuse supplies battery positive voltage to the coil side of the cooling fan 1 relay.
  4. 5. Verifies that the PCM is providing ground to the cooling fan 1 relay.
  5. 6. Tests for voltage at the coil side of the cooling fan 2 relay. The cool fan 2 fuse supplies battery positive voltage to the coil side of the cooling fan 2 and cooling fan 3 relays.
  6. 7. Verifies that the PCM is providing ground to the cooling fan 2 relay.
  7. 8. Verifies that the PCM is providing ground to the cooling fan 3 relay.
  8. 9. Tests if ground is constantly being applied to the cooling fan relays.
  9. 10. Test the control circuit of the cooling fan relays for a short to voltage or an open.
  10. 11. Test the control circuit of the cooling fan relays for a short to ground.
  11. 12. Test the battery positive voltage circuit for a short to ground.
Fig 1: DTC P0480 Or P0481 Diagnostic Procedure (Steps 1 - 12)
G01969555Courtesy of GENERAL MOTORS CORP.
Fig 2: DTC P0480 Or P0481 Diagnostic Procedure (Steps 13 - 22)
G01969556Courtesy of GENERAL MOTORS CORP.