alhutch
Veteran Member
I'm trying to solve an issue on my new to me 2004 wagon. I noticed that the auxiliary fan runs whenever the ignition is on (car running or not), regardless of coolant temp, with A/C switch OFF.
I changed the coolant temp sensor at the base of the radiator yesterday hoping this might cure it (also easiest fix), but no dice. Checked the "second speed" fan relay (relay 370 on the second relay panel) under dash and it is clicking to start the fan about 5-10 seconds after turning ignition switch on, but not starting the car. Dash A/C switch is OFF and HVAC fan switch is also OFF.
I also swapped relay 370 with the load reduction 370 to see if the fan relay might be wonky, but same behavior with the other relay.
VCDS Group 007 shows coolant temp on a stone cold motor to be ambient (18º C), which shouldn't trigger the fan to run.
Car did have the following code set when I got it, so maybe this will help or point in the right direction:
16512 - Coolant Thermostat Valve (N214)
P0128 - 000 - Temperature below Control Range
Freeze Frame:
RPM: 1638 /min
Torque: 164.0 Nm
Speed: 60.0 km/h
Temperature: 67.5°C
Fuel Consump.: 6.00 l/h
Temperature: 43.2°C
Temperature: 43.2°C
Absolute Pres.: 1428.0 mbar
Fan does shut off with the key, so not an after-run issue at this point.
Any thoughts as to where I might look next to find why the ECU is signaling to start the low speed fan? Thanks for any ideas.
I changed the coolant temp sensor at the base of the radiator yesterday hoping this might cure it (also easiest fix), but no dice. Checked the "second speed" fan relay (relay 370 on the second relay panel) under dash and it is clicking to start the fan about 5-10 seconds after turning ignition switch on, but not starting the car. Dash A/C switch is OFF and HVAC fan switch is also OFF.
I also swapped relay 370 with the load reduction 370 to see if the fan relay might be wonky, but same behavior with the other relay.
VCDS Group 007 shows coolant temp on a stone cold motor to be ambient (18º C), which shouldn't trigger the fan to run.
Car did have the following code set when I got it, so maybe this will help or point in the right direction:
16512 - Coolant Thermostat Valve (N214)
P0128 - 000 - Temperature below Control Range
Freeze Frame:
RPM: 1638 /min
Torque: 164.0 Nm
Speed: 60.0 km/h
Temperature: 67.5°C
Fuel Consump.: 6.00 l/h
Temperature: 43.2°C
Temperature: 43.2°C
Absolute Pres.: 1428.0 mbar
Fan does shut off with the key, so not an after-run issue at this point.
Any thoughts as to where I might look next to find why the ECU is signaling to start the low speed fan? Thanks for any ideas.