Cooling fan RES speed control short circuit to ground.
• Check connectors to BMU (E81) C15 • For FPC1(B) - Check wiring between BMU and cooling fan RES and harness connector C443 pin 3 - Disconnect the connector C443 and the cooling fan RES and the BMU E81 A, b and C connector and measure the resistance on the fan side of the harness between pin 3 and 13 and then pin 3 and 18. - If the resistance is measurable(< OL) change the harness to the cooling fan RES M39. - Connect the fan and measure the resistance on the fan side of the harness between pin 3 and 13 and then pin 3 and 18. - If the resistance is measurable(< OL) change the cooling fan RES M39. - Measure the resistance on the BMU side of the harness between pin 3 and 13 and then pin 3 and 18. - If the resistance is measurable(< OL) harness to the BMU E83 - If the resistance is infinite or OL, change the BMU(E81) • For FPC1(A) - Check wiring between BMU and cooling fan RES M39. - Disconnect the fan and connector E81A, B and C and measure the resistance between pin C15 and pin A2 in the harness connector. - If the resistance is measurable(< OL) change the harness to the cooling fan RES M39 - Connect the fan and measure the resistance between pin C15 and pin A2 in the harness connector. - If the resistance is measurable(< OL) change the cooling fan RES M39 - If the resistance is infinite or OL, change the 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
Electrical error diagnosis in BMU
• Short circuit in connection to BMU • Short circuit in wiring between cooling fan RES and BMU • Short circuit in the cooling fan RES