There is an error with the digital feedback signal from the cab fan (M3).
1. Check the cable harness, including the cable harness for the cab fan control signal and the supply. 2. Replace the cab fan.
What you'll see
No driver-visible symptom recorded.
System reaction
It will not be possible to determine if the cab fan is working or not, or at what speed it is running. This might affect the control system performance.
Diagnostic depth
The climate control system (E17) has registered an implausible value on the digital feedback signal from the cab fan. The test is performed when the cab fan is running and the starter motor (M1) is not running.
1. The feedback signal cable harness is open, or 2. The feedback signal cable harness is short circuit to ground, or 3. The feedback signal cable harness is short circuit to battery, or 4. The cab fan has shut off due to a voltage fault, or 5. There is a non detectable electrical error on the cab fan control signal, or 6. The cab fan electronics are broken.