Removing/installing and renewing air conditioner compressor regulating valve N280 — AUDI

🧭 Before you start

Fits: Audi A5 (8T, 2007–2016), Audi Q5 (8R, 2008–2017), Audi A2 (8Z), Audi A3 (8L, 1996–2003), Audi A4 B5 (8D), Audi A4 B6/B7 (8E), Audi A4 B9 (8W, 2015–), Audi R8 (4S, 2015–), Audi A5 Cabriolet (8F), Audi A6 C5 (4B), Audi A8 D2 (4D), Audi A8 D3 (4E, 2002–2010), Audi A3 (8P, 2003–2012), Audi A4 Cabriolet B6/B7 (8H), Audi TT Mk1 (8N), Audi A6 C6 (4F, 2004–2011), Audi A4 B8 (8K, 2007–2015), Audi Q7 (4L, 2005–2015), Audi A3 (8V, 2012–2020), Audi Q7 (4M, 2015–), Audi A8 D4 (4H, 2010–2017), Audi TT Mk2 (8J, 2006–2014), Audi A6/A7 C7 (4G, 2011–2018), Audi A1 (8X, 2010–2018), Audi Q3 (8U, 2011–2018); platform codes 8C, 4A, 8G, 85, FV, 42, 83, 84, 4X

• Opens: refrigerant (A/C)
• Renewed: connector, air conditioner compressor
• Also covered elsewhere: Electronic parts catalogue) Electrical system97Connectors

Don't miss

• With the air conditioner compressor in position, a refrigerant line has to be detached to ensure that the pressure in the air conditioner compressor is the same as the ambient pressure.
• If refrigeration oil has emerged with N280(B) removed, use the air conditioner service station to add this quantity of refrigeration oil when charging the refrigerant circuit Working with the air conditioner service station .

📋 Procedure

1. Drain the refrigerant circuit Working with the air conditioner service station.
2. ⚠ Risk of air conditioner compressor damage if the refrigerant circuit is emptyNever start the engine when the refrigerant circuit is empty.Depending on the version of the air conditioner service station, the pressure in the refrigerant circuit may be less than 1 bar absolute following drainage.Depending on the version, the air conditioner compressor may be damaged by running it when the pressure in the refrigerant circuit is low.Never start the engine if the pressure in the refrigerant circuit is below ambient pressure. — Depending on the vehicle and the installation location of the air conditioner compressor, remove the components impeding access to N280Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).
3. Removing the air conditioner compressor Heating, air conditioning87Air conditioner compressor (vehicle-specific Workshop Manual). [Note: With the air conditioner compressor in position, a refrigerant line has to be detached to ensure that the pressure in the air conditioner compressor is the same as the ambient pressure.]
4. ⚠ Risk of injury (frostbite).Before removing N280, connect the air conditioner service station and extract refrigerant. The refrigerant circuit must be empty; danger of injury.Refrigerant and refrigerant oil will emerge if the refrigerant circuit has not been drained.The refrigerant is to be extracted before removing N280. Renewed evaporation may create pressure in the refrigerant circuit if N280 is not removed within 10 minutes following extraction. Extract refrigerant again. — Check the pressure in the refrigerant circuit again by way of the pressure gauge of the air conditioner service station.
5. Detach one of the two refrigerant lines from the air conditioner compressor Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual). [Note: With the air conditioner compressor in position, a refrigerant line has to be detached to ensure that the pressure in the air conditioner compressor is the same as the ambient pressure.]

6. Before removing N280, check again whether the air conditioner compressor is actually being driven by the pulley/drive unit. If the overload protection device of the pulley or drive unit has been tripped, the malfunction is usually not caused by the regulating valve, but by the air conditioner compressor (e.g. because it is stiff). [Note: This illustration shows N280(B) for a "“Sanden”" air conditioner compressor of type "“PXE 14”". With these air conditioner compressors, the connector for connection to the vehicle wiring harness is attached directly to N280(B). Removal and installation of N280(B) for other air conditioner compressors (different type, different make e.g. "“Denso”", N280 with a short wiring harness to the connector for example) may differ. The basic procedure is however the same, as described below for the "“Sanden”" air conditioner compressor of type "“PXE 14”".This illustration shows an N280(B) with an O-ring (E) (not fitted on all versions).In the case of an N280(B) with no O-ring (E), dirt may ingress into the mounting for N280(C) as far as the O-ring (F).]
7. If fitted, unfasten the wiring from N280(B) to the vehicle wiring harness connector from the air conditioner compressor. [Note: On air conditioner compressors with air conditioning system magnetic clutch N25 on which N25 is activated via the same connector as N280(B), eject the corresponding wires from the connector (e.g. with an ejector from the wiring harness repair setVAS 1978 B) Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).If an air conditioner compressor with air conditioning system magnetic clutch N25 has a connector from which the electrical wires cannot be ejected, sever the wires to N280 (or to N25) at a suitable location and re-connect using wiring connectors from the wiring harness repair setVAS 1978 B (or renew the connector; refer to Electronic parts catalogue) Electrical system97Connectors; Repairing electrical wiring harnesses and electrical connectors.]
8. Thoroughly clean the air conditioner compressor in the area of the circlip (A) and N280(B).
9. ⚠ The pressure in the air conditioner compressor must be the same as the ambient pressure.Refrigerant and refrigeration oil may emerge in the event of higher pressure in the air conditioner compressor.Dirt may be drawn into the air conditioner compressor in the event of lower pressure in the air conditioner compressor.Ensure pressure equalisation before removing N280(B). — Remove the circlip (A).
10. Carefully remove N280(B) from the mounting on the air conditioner compressor (C) using a suitable screwdriver (D) for example.
11. After removal, check N280(B) and the mounting on the air conditioner compressor (C) for contamination. [Note: If the strainer (D), N280(B) as far as the O-ring (F) or the mounting on the air conditioner compressor (C) is severely contaminated in this area (e g. with swarf or dark, tacky abrasion), this is an indication of air conditioner compressor damage. In this case, clean the refrigerant circuit and replace the air conditioner compressor Renewing air conditioner compressor on account of leakage or internal damage and Cleaning (flushing) refrigerant circuit with refrigerant R134aIf the strainer (D) at N280(B) and the mounting on the air conditioner compressor (C) as far as the sealing surface of the O-ring (F) are only slightly contaminated (e g. with light grey deposits from normal air conditioner compressor operation), the cause of air conditioner compressor malfunctioning may be a problem with N280(B).If N280(B) does not have an O-ring (E), dirt may have entered the mounting (C) as far as the O-ring (E) during operation. Carefully remove all dirt using a lint-free cloth or similar (do not use compressed air).]
12. Check the mounting on the air conditioner compressor (C) and the groove for the circlip for contamination and clean carefully and thoroughly with a fresh lint-free cloth if necessary.
13. ⚠ Dirt in the air conditioner compressor or damage to the sealing surfaces in the mounting could lead to renewed failure of N280(B) or the air conditioner compressorIf necessary, carefully clean the mounting on the air conditioner compressor (C) with a fresh lint-free cloth (do not use compressed air).When cleaning the mounting (C), make sure no dirt ingresses into the area beneath the sealing surface for the O-ring (F) or into the ducts provided and that none of the sealing surfaces of the mounting are damaged. — Check mounting for air conditioner compressor (C) for damage (also check for small scratches on the surface; renew air conditioner compressor if damage is found).
14. Check the O-rings (F,G,H) and (E) (if fitted) of N280(B) for damage.
15. Moisten the O-rings (F,G,H) and (E) (if fitted) of N280(B) with a small quantity of refrigeration oil and check for proper attachment.
16. Insert N280(B) as far as it will go in the mounting on the air conditioner compressor (C).
17. Fit a new circlip (A) and check for correct positioning in the groove.
18. Re-install all parts removed in reverse order.
19. Evacuate and re-charge the refrigerant circuit Working with the air conditioner service station. [Note: If refrigeration oil has emerged with N280(B) removed, use the air conditioner service station to add this quantity of refrigeration oil when charging the refrigerant circuit Working with the air conditioner service station .]
20. Check operation of the air conditioner Checking pressures and Heating, air conditioning87Refrigerant circuit; System overview - refrigerant circuit (vehicle-specific Workshop Manual).

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