Cooling fan RES underperforming.
For FPC1(A) • Check the cooling fan RES fuse No49 in P2 For FPC1(B) • Check the cooling fan RES fuse No4 in F564 For FPC1(A or B) • Check the cooling fan wiring harness for chafing or other faults • Check cooling fan RES connector M39-A and BMU E81-B are properly connected and the pins are clean and free from oxide. • Have ignition on, Disconnect M39-A and measure the voltage on the cable between M39-A1 and M39-A2. If the voltage is <22V, perform a troubleshooting on the feeding cable to the fan and the 24V-system. • Check that fan can spin freely and that it is free from foregein objects. • Check that the radiator flanges are clean and free from foregein objects. • Change the Cooling fan RES (M39). • Change BMU(E81).
What you'll see
No driver-visible symptom recorded.
System reaction
No additional reaction. System performance might be reduced due to high temperatures.
Diagnostic depth
During low utilization on the battery cooling system the fan is ran at high speed and the decrease in temperature difference on the coolant is evaluated before and after. The test is ran about every second week of operation.
• Fan is not connected. • Fan is stuck. • Fan fuse is blown. • Radiator is clogged or broken. • Fan supply cabling is damaged or faulty.