Air con fan not working, with VCDS

[Aeroelastic]

Hi,

Hope all are well. I have an issue with my aircon. The car is a 2.0 tdi BRE engine. My aircon fan is not running when I turn on the aircon and it doesn't blow cold air. The radiator fan is working when the aircon s switched on and off though... Below is the VCDS output after the car run for 20mins. There is no fault codes from the HVAC section.

0.652A N280 current
62.4%. N280 Duty Cycle
18.5% High pressure signal G65
4.0 bar Refrigerant circuit pressure

The compressor shut off reading are:

0.0 Current criteria
1.0. Last criteria
0.0 last but one criteria
0.0 last but two criteria2A

Can anyone help please? Is it likely to be compressor?

Thanks

[fly300kts]

Perform a fan test using the feature in VDCS

Phil

[Aeroelastic]

Perform a fan test using the feature in VDCS

Phil

Thanks. How do I do that in VCDS?

[fly300kts]

http://www.ross-tech.com/vcds/tour/out_test.html

Phil

[Aeroelastic]

Thanks. Can't seems to select the criteria I want to test, it's grey out. this is a VCDS borrowed from a friend... Any other way to test the AC fan? I can see the radiator fan % changing when turning aircon On and Off from Measuring Blocks. But not AC fan.

I noticed that my pressure for refrigerant stays at 4bar and did not move whether the car is running or not or when the aircon is On or Off, suggesting that the compressor is not running?

[mitchell.]

Thanks. Can't seems to select the criteria I want to test, it's grey out. this is a VCDS borrowed from a friend...

Are you sure the cable is genuine ?

[Aeroelastic]

Are you sure the cable is genuine ?

Not sure about cable..

I noticed this jet plane sound from the aircon fan awhile ago when I turn off engine after a drive. Obviously with air con on. Might be the fan packed up?
In Audi system, will the compressor be automatically shut down if the fan is not working to avoid overheating?
Or the other way round, the fan rely on whether the compressor is on or off?

[Aeroelastic]

Hi, can anyone advise how to test the ac fan physically? I meant by jumping a12v to the connector. This is the smaller fan for the Ac.

Iran output test on VCDS and only the big fan come on, not the smaller one.

Thanks.

[Okedokey]

Check fuses.

[Aeroelastic]

Fuses checked.. Those below steering column.. All looks ok..

[1killera4]

Bad Fan or fan Control Module. Happened to me. Just replace them both and the Module all at once. The bumper has to come off.

[Aeroelastic]

I found the below, Is step 1-6 done by using VCDS or a voltmeter?:

In case the link disappears in the future: "On this vehicle, the cooling fan and A/C compressor operation are controlled by the J293 fan control module, which is usually located in the driver's front corner of the engine compartment on the lower frame rail. The J293 module has both a 14-pin connector identified as the T14 connector in Volkswagen wiring diagrams and a four-pin connector identified as the T4a connector. To diagnose this system, starting on the T14 connector:

1) Start and idle the vehicle. Select "A/C on" at maximum cooling and "blower on" at high speed.

2) Check for 12 volts at the T14 connector pin No. 8 (T14/8). This 12-volt signal comes from the A/C switch and requires both cooling fans on at low speed and compressor activation.

3) Check for 12 volts at pin T14/9. This voltage is a switched ignition source and will have 12 volts when the ignition is in the "on" position.

4) Check for 12 volts at pin T14/4. This is a constant battery source and should read 12 volts at all times from fuse S16.

5) Check for a good ground at pin T14/6.

6) Check for 12 volts at all times at the four-pin connector, T4a pins T4a/1 and T4a/3 from fuses S164 and S180, respectively.

7) Turn off the ignition. Remove the T14 connector and check for continuity between pins T14/14 and T14/5 on harness side to ensure proper operation of the F38 ambient temperature switch. Continuity must be present if the ambient air temperature is above 32 degrees Fahrenheit. Reconnect the T14 connector and restart the vehicle.

8) Check pin T14/2 using a duty cycle meter. If the refrigerant charge in the system is normal, about 30 percent to 35 percent duty should be indicated at pin T14/2 without the compressor engaged. The duty cycle signal is supplied by the G65 pressure sensor in response to system pressure changes. A duty cycle above 90 percent or below 20 percent will command the compressor off.

9) Check for an 11-volt reference voltage at pin T14/3. The reference voltage originates in the J293 fan control module and can be grounded by |the power control module (PCM) under certain circumstances (typically wide open throttle or vehicle overheat conditions) to turn the A/C compressor off.

If zero volts are present, the PCM is commanding "compressor off" or the wiring harness is shorted to ground. Raise vehicle idle speed above 2500 rpm and observe compressor operation and voltage at pin T14/3. If the voltage at pin T14/3 returns to 11 volts with the idle speed above 2500 rpm and compressor operation resumes, then a throttle basic setting procedure is needed and must be performed with a factory-compatible, by-directional scan tool. Note: A loss of throttle basic settings will keep the compressor from activating.

If all previous tests have passed, check the T14 connector pin T14/10 for 12 volts. This pin is the output signal to the compressor clutch coil. If all the other tests have passed and there is no voltage at pin T14/10, this indicates a faulty fan control module."