Cooling Fan Functional Check

Perform Powertrain On-Board Diagnostic (OBD) System Check in under appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If no DTCs are present, go to next step.
Install scan tool. Engine coolant temperature must be less than 212°F (100°C) for all fan diagnoses. Turn Ignition on, engine and A/C off. If cooling fans are off, go to next step. If cooling fans are not off, see PROCEDURE NO. 1 .
Using scan tool, command low speed fans on. If both cooling fans are on, go to next step. If both cooling fans are not on, see PROCEDURE NO. 2 .

NOTE: Allow a 3-5 second delay before determining if fans have switched from low to high speed.

Using scan tool, command high speed fans on. If both cooling fans switch to high speed, go to next step. If both cooling fans do not switch to high speed, see PROCEDURE NO. 3 .
Exit outputs screen on scan tool. Idle engine leaving A/C OFF. If cooling fans on, go to step 7.
Turn A/C on. If cooling fans are on, system is okay. If cooling fans are not on, go to step 8.
If scan tool displays A/C request as YES, see TESTING in appropriate MANUAL A/C-HEATER SYSTEMS article. If scan tool does not display A/C request as YES, go to step 9.
If scan tool displays A/C request as YES, see appropriate A/C COMPRESSOR CLUTCH CONTROLS article. If scan tool does not display A/C request as YES, see TESTING in appropriate MANUAL A/C-HEATER SYSTEMS article.
Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE.