BMW X5.- Frequent breakdowns

bmw-x5

BMW X5 (E53) automatic with V8 engine 4.4i

Symptom 
The ZF 5HP24 automatic gearbox does not change ratios 4 and 5. 
Two codes are registered: 
– 22 gearbox oil temperature sensor, 
– 3D gearbox faulty gearbox.

Fault
The possible causes of the fault are:

– The gearbox sensors are defective (inlet and outlet speeds, oil pressure and temperature). 
– The sequence solenoid valves are defective. 
– Defective brakes or clutches.

To make an appropriate diagnosis, it is recommended to follow the following steps:

1. Carry out a fault reading on the automatic gearbox computer. The presence of two failures is confirmed. 
2. Check the oil temperature of the gearbox in real values. It is verified that there are abrupt variations of the information relative to the temperature of the oil (for example, it goes from 116ºC to 70ºC in a few seconds). 
3. Check the wiring of the oil temperature probe. Variations of resistance appear by moving the wiring. The temperature of the crankcase of the oil of the box is detected by means of a thermistor welded inside the wiring of the gearbox.

NOTE: The temperature of the oil pan of the gearbox serves as a criterion for the control of the clutch of the torque converter.

Solution
Replace the wiring of the gearbox.