Checking cooling output - manually controlled air conditioner — AUDI

🧭 Before you start

Fits: Audi Q3 (8U, 2011–2018); platform code 84

• Renewed: sender

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• Measure ambient temperature (it must be over 15 °C).

📋 Procedure

1. Measure ambient temperature (it must be over 15 °C).
2. Close doors, bonnet, windows, sun roof and rear lid.
3. Open all dash panel vents.
4. Start engine.
5. Switch air conditioner compressor off (lamp in AC or A/C button (2) does not light up).

6. "“Read measured values”" in "“Guided Fault Finding”" mode for air conditioner .
7. Read out activation of air conditioner compressor regulating valve N280.
8. Read out measured value for high-pressure sender G65. [Note: On the absolute pressure scale, 0 bar corresponds to an absolute vacuum. Normal ambient pressure thus corresponds to roughly 1 bar absolute and 0 bar gauge pressure. On the scales of most pressure gauges, 0 bar gauge pressure corresponds to an absolute pressure of 1 bar (can be seen from -1 mark below 0).Depending on the version of J301, the measured values may only be displayed as whole numbers. The display fluctuates between two values if the measured pressure is between the two.The pressure in the refrigerant circuit depends on the ambient temperature. Due to the radiation of heat by components (e.g. radiator), the pressure displayed when the engine is warm is slightly higher than that given for the corresponding ambient temperature.]
9. Check signal from high-pressure sender G65 ("“Guided Fault Finding”") and Checking pressure signal from high-pressure sender G65.
10. If no fault is found at the high-pressure sender G65, there is not enough refrigerant in the circuit. Take the vehicle to a workshop equipped with the necessary tools where the work can be performed by appropriately qualified personnel Air conditioner with refrigerant R134a87General notes on air conditioning systems.
11. "“Read measured values”" in "“Guided Fault Finding”" mode for air conditioner .
12. Check display in display zones: [Note: If the pressure indicated does not change and activation of the air conditioner compressor is OK, check again whether the calculated current is actually flowing via the air conditioner compressor regulating valve N280 and whether the air conditioner compressor is actually being driven. If the current is actually flowing via N280 and the air conditioner compressor is being driven, there is a fault in the refrigerant circuit. Take the vehicle to a workshop equipped with the necessary tools where the work can be performed by appropriately qualified personnel Air conditioner with refrigerant R134a87General notes on air conditioning systems. There may be problems with the control of the air conditioner compressor. Inform the workshop of the problem detected.N280 is activated by J301 so that the temperature of the air downstream of the evaporator reaches the specified value (approx. 2 to 5 ℃).After starting the vehicle, a value above 0.55 A is displayed for the activation of N280 depending on the measured temperature, engine speed and electrical system voltage. As soon as the temperature measured by the evaporator output temperature sender G263 approaches the specified value, activation is cancelled and the compressor output thus reduced.Under certain operating conditions, residual moisture in the refrigerant circuit may lead to the formation of ice at N280 (and at the expansion valve). Such ice formation impedes the control of the air conditioner compressor. The evaporator is cooled down too much and ices up. An iced-up evaporator may cause various problems .If no current is displayed in the measured values for the activation of the air conditioner compressor regulating valve N280 or if the current is too low, check the activation of N280 ("“Guided Fault Finding”").Certain malfunctions of N280 (e.g. sticking valve or open circuit in coil) can lead to problems with the air conditioner compressor (no cooling output from air conditioner, evaporator icing up etc.). If N280 (and not the air conditioner compressor itself) is the cause of the problem, the air conditioner compressor can be serviced by renewing N280Air conditioner with refrigerant R134a87Renewing components of refrigerant circuit.N280 is not available as replacement part for all air conditioner compressors. If N280 cannot be obtained separately for a particular air conditioner compressor (different versions available), the entire air conditioner compressor must be renewed if problems occur Electronic parts catalogue.]
13. Press "Air recirculation" button (3) on operating unit (air conditioning system control unit J301).
14. Set engine speed to 2000 rpm (start of time measurement).
15. "“Read measured values”" in "“Guided Fault Finding”" mode for air conditioner .
16. Compare measured value displayed for evaporator output temperature sender G263 to values in graph.
17. Measure temperature of air emerging from dash panel vents using a thermometer. [Note: If the measured values only differ slightly, perform the measures to be taken if the readout does not match the specification . If the measured value for the evaporator output temperature sender G263 is higher than your measured value, check that G263 is correctly installed and perform the electrical checks for this sender .The operation of the air conditioner can be detected e.g. from the fact that the refrigerant pipe on the low-pressure side (thick pipe) cools down.]
18. Measure temperature of air emerging from dash panel vents (left and right) using a thermometer.
19. Measured values may not be lower nor (after 5 minutes) more than 3° C higher than value for evaporator output temperature sender G263. [Note: If the measured values obtained are lower, check that evaporator output temperature sender G263 is installed correctly and check electrical wiring for contact resistance; renew sender if defective.If the specified values are not attained, check activation and operation of temperature flap. To do so, perform the measures to be taken in the event of a temperature increase downstream of the evaporator and .]

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