Sport Radiator fan on constantly

Range Rover Sport (L494) 3.0 D 4x4 Diesel 292 hp / 215 kW

Hi All,

My range has recently developed a problem with the cooling fan. It is on constantly from about 5 seconds after ignition until it is turned off.

I have done an OBD diagnostic and fault code P0480 shows up
"Engine coolant blower motor 1 - circuit malfunction"

I need to get into doing some circuit tests which will hopefully do tomorrow however after researching the code I noticed that faulty coolant temp sensor can cause this and also a faulty VSS sensor...

So, I ran a live road test and checked the sensor read outs. coolant temp sensor seems fine and held at about 90C

When I checked the Vehicle Speed Sensor it showed no speed on any of the wheels. The general speed sensor also showed max speed of 10mph (I hit 50 on the road test). Average speed showed as 0.4pmg for the entire test. The speedo works fine and no problems so I assume this is measured else where.

After researching generally on other cars the VSS seems to be mounted on the gear box casing however when looking for parts for my range I only seem to be able to find the wheel sensors online and no mention of a transmission VSS.

Is there a central VSS on the L494 that feeds diagnostics with vehicle speed from the transmission and if so where is it located? Obviously i'm not getting a read on the VSS despite the diagnostics dashboard reading the speed correctly.

Also is there a relay involved in the speed sensors - maybe ABS related? If so where would it be located.

Thanks for your time.

Range Rover Sport (L494) 3.0 D 4x4 Diesel 292 hp / 215 kW

The speed not showing on a diagnostic is a red herring, and not relevant. The speed data is available on the CAN as the speedometer is functioning.

There is likely an issue with the fan controller module, which is normally located on the fan assembly.
Most fan control modules power the fans by getting a PWM signal from the ECM, and run the fans in response to the PWM signal received.
If the fans are running at full speed, it's likely that the PWM is missing.

Also don't forget that the fans will run under the control of the HVAC system, so if the HVAC needs additional cooling, the fans will also run, which is normal.

Thanks for this, thats really helpful. I have done a bit more investigation and ruled out fuses/relays etc... that may be causing an open circuit. The cooling fan has an integrated motor and control unit so I am looking at swapping out the entire cooling fan assembly if it's the control module at fault.

Before I do that I am waiting for a wire tracer to arrive so I can track the control wires from fan1 up the wiring loom, I have spotted an area of the loom under the air cleaner that looks suspect, we have also had intermittent failure of the indicator which runs down the same loom so looks promising that this is a circuit problem and the ECM has lost comms with the fan control module. Will need to remove the air cleaner to get access to the section of wiring i need to inspect so will so that this week.

Thanks again for the help on the VSS - saved me a ton of time.

Some further info from diagnostics:

P0480- 13 Fan 1 Control Circuit - Circuit open
Possible Causes
The engine control module has determined an open circuit via lack of bias voltage, low current flow, no change in the state of an input in response to an output Fan 1 control circuit - Open circuit
Cooling fan 1 component failure
Action
Using the manufacturer approved diagnostic system check datalogger signals, Electric Fan PWM Control - Commanded (0x03F9). Refer to the electrical circuit diagrams and check the cooling fan 1 control circuit for open circuit. Check the power and ground supplies to the cooling fan 1 control module. Repair harness as required. Clear DTC and retest
Check and install new cooling fan 1 control module as required