Fan speed
â–¶ How to fix
Measure fan speed sensor supply (12 V). If sensor supply voltage is available, measure pulse signal from sensor (Hall sensor with 6 pulses per revolution). If internal fault in fan hub unit is suspected, replace hub unit.
What you'll see
No driver-visible symptom recorded.
System reaction
Engine will run in normal fan mode without feedback. Fan will work but with reduced functionality, resulting in increased engine temp at some operating conditions, and increased fan noise at low vehicle speeds.
Diagnostic depth
Detection
The fan speed feedback signal has been below normal.
Possible cause
Fan speed sensors or its connection is defect, fan is stuck or belt is broken.