P0691 and P0483

[miruim]

Hello and a Great 2025 to all.

I have a c5 x7 9hz Motor.
One moth ago i found errors with diagbox P0691 and P0483 .
All suposed to be a cooling fan problem. The fan works in the normal speed, and when i turn the AC On the the Fan starts working in High speed.

I have tested with diagbox the normal speed and works good. When i test the high speed, the fan begins and then stops.
I have checked all wires till ECU and all are ok.
I have checked with a new one cooling Fan and the errors are the same. the P0483 i can clear, but sometimes it appairs again.

the water is cold and i dont know how to solve this problem .

Can someone help me with a clue ?

Best regards to all

[miruim]

any clue that can help me , please ??

[GiveMeABreak]

Both these errors relate to open and short circuits - so did you replace the electronic cooling fan unit and not just the fan? If so, check the wiring.

Fault Code:	P0691
Description of Fault:	Fast speed cooling fan control: Short-circuit to earth or short-circuit to the battery plus or excessive temperature. Description of the diagnostics: The ECU detects a short-circuit to the battery plus or a short-circuit to earth or an excessive temperature on the fast speed cooling fan control channel for 5 seconds.
Conditions for Fault to clear:	Ignition on
Downgrade Modes whilst Fault is active:	Diminution of the coolant temperature thresholds to cut the aircon compressor
Symptoms:	Fan unit at high speed Water temperature warning Engine overheating
Suspect Areas:	Electrical harness Connector

Fault Code:	P0483
Description of Fault:	Cooling Function Incorporated in the ECU ( electric cooling fan unit): Open circuit. The line is in open circuit for more than 5 seconds
Conditions for Fault to clear:	Ignition on
Downgrade Modes whilst Fault is active:	Diminution of the coolant temperature thresholds to cut the aircon compressor
Symptoms:	The cooling fan to operate permanently at maximum speed Battery discharged
Suspect Areas:	Electric cooling fan unit Electrical harness Connector

[miruim]

I have changed all the wires and relay, not just the fan.. Checked the wires to the ECU and all are ok.

[GiveMeABreak]

Well I can only tell you what the code is officially relating to, so either there is something else in the control unit not working or it's just not happy about it.