Checking heat output of air conditioner — AUDI

🧭 Before you start

Fits: platform code 42

• Special tools named: VAS 5051

Don't miss

• If the charge of the batteryA is too low, connect the battery chargerVAS 5900 for example to the vehicle.

📋 Procedure

1. Check operation of the left heat regulation valve N175, right heat regulation valve N176 and coolant circulation pump V50"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
2. Check the coolant hoses (from engine to coolant circulation pump V50 and from heating system heat exchanger back to engine) for interchange and cross-sectional restriction Engine, mechanics19.
3. Check for interchanged electrical contacts of the coolant circulation pump V50. Direction of pump rotation .
4. Check for interchanged contacts of the left heat regulation valve N175 and the right heat regulation valve N176 as well as for correct incorporation of these valves into the coolant circuit.
5. Close the front lid, doors and windows.

6. Open all dash panel vents.
7. Start the engine and make the following settings on the operating unit, Climatronic control unit J255:
8. Operate the air conditioner (with the engine running) for several minutes at maximum cooling output.
9. Switch off the ignition.
10. With the ignition switched off, connect the vehicle diagnostic, testing and information systemVAS 5051/ by way of the diagnostic cableVAS 5051/5A to the 16-pin diagnostic socket in the vehicle Vehicle diagnostic, testing and information systemVAS 5051/ "Guided fault-finding" function.
11. Switch on ignition.
12. Start air conditioner guided fault-finding "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
13. Alternately select the display group with the following values in the "“Reading measured value block”" function: Actuation of the left heat regulation valve N175, the right heat regulation valve N176, the air conditioner compressor regulating valve N280 and the coolant circulation pump V50 and the measured values of the left vent temperature sender G150 and the right vent temperature sender G151 and check the display in the measured value block "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
14. Set a medium fresh air blower speed on the rotary blower control (of the operating unit, Climatronic control unit J255). [Note: The temperature of the air emerging from the heating system heat exchanger is displayed by the measured values of the left vent temperature sender G150 and the right vent temperature sender G151Vehicle diagnostic, testing and information systemVAS 5051/, "Guided fault-finding" function. Following removal of an operating unit, Climatronic control unit J255 from the centre console (the electrical connections are not to be detached when doing so), the coolant and refrigerant lines are accessible by way of the mounting slot and their temperature can thus be felt (removing operating unit, Climatronic control unit J255). To determine whether the coolant lines cool down, carefully grasp hold of them through the mounting slot in the dash panel (the lines could still be hot).]
15. Read out the measuerd values for the charge status of the batteryA (no undervoltage shutoff by onboard supply control unit J519) Vehicle diagnostic, testing and information systemVAS 5051/, "Guided fault-finding" function. [Note: If the charge of the batteryA is too low, connect the battery chargerVAS 5900 for example to the vehicle.]
16. Read out the measured values of the left vent temperature sender G150 and the right vent temperature sender G151Vehicle diagnostic, testing and information systemVAS 5051/, "Guided fault-finding" function.
17. On the operating unit, Climatronic control unit J255, set the rotary temperature control to the "“Warm”" stop.
18. Compare the measured values for G150 and G151. [Note: Following removal of an operating unit, Climatronic control unit J255 from the centre console (the electrical connections are not to be detached when doing so), the coolant and refrigerant lines are accessible by way of the mounting slot and their temperature can thus be felt (removing operating unit, Climatronic control unit J255). To determine whether the coolant lines become warm, carefully grasp hold of them through the mounting slot in the dash panel (the lines may be hot).]
19. On the operating unit, Climatronic control unit J255, set the rotary temperature control to the "“Cold”" stop again.
20. Compare the measured values for G150 and G151Vehicle diagnostic, testing and information systemVAS 5051/, "Guided fault-finding" function.

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