Removing auxiliary/supplementary heater: Audi Q7

🧭 Before you start

Fits: Audi Q7 (4L, 2005–2015)

• Special tools named: VAS 5051

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• On installation, secure the cover (B) with new shear bolts (A)Electronic parts catalogue.
• Mark the position of the coolant hoses.

📋 Procedure

1. Interrogate the encoding and adaption of the supplementary heater control unit J364 by way of the "“Control unit replacement”" function of the guided fault-finding routine "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
2. Switch off ignition and auxiliary/supplementary heater.
3. Dissipate the pressure in the coolant circuit by opening the cap at the coolant expansion tank Engine, mechanics19.
4. Remove the front left wheel housing liner General body repairs, exterior63.
5. Drill out the shear bolts (A) with a dia. 3.0 mm bit.

6. Screw a commercially available left-hand removal tool for example (size -3-) into the hole of the shear bolts (A) and unfasten the bolts.
7. Remove the cover (B). [Note: On installation, secure the cover (B) with new shear bolts (A)Electronic parts catalogue.]
8. Release the 6-pin connector (B) by pressing it towards the component, release the catch whilst pressing the connector (e.g. by pulling tab) and unplug the connector.
9. Wait 2 seconds, then release the 2-pin connector (A) by pressing it towards the component, release the catch whilst pressing the connector (e.g. by pulling tab) and unplug the connector. [Note: Observe the correct sequence when unplugging the connectors. Unplug the 6-pin connector first, wait 2 seconds and then unplug the 2-pin connector.Unplugging the 2-pin connector first could result in a fault being stored in the supplementary heater control unit J364, which can then only be erased after unplugging the connectors and plugging them in again in the correct sequence.On connection, plug in the 2-pin connector first, wait 2 seconds and then plug in the 6-pin connector.]
10. Mark the position of the coolant hoses.
11. Pinch off the coolant hoses (supply and return to heat exchanger in front air conditioning unit) using hose clamps up to dia. 25 mm3094 for example.
12. Pinch off the coolant hoses (supply and return to engine) using hose clamps up to dia. 25 mm3094 for example. [Note: Contrary to the illustration, the coolant hoses from and to the heat exchanger in the rear air conditioning unit are additionally to be pinched off on vehicles with "“rear air conditioner”" as optional extra Heating, air conditioning87.If the coolant hoses are not long enough to be pinched off, trace the supply and return to the engine/heat exchanger in the rear air conditioning unit and pinch off the downstream coolant hoses in the coolant circuit Heating, air conditioning87.]
13. Unfasten the clamps (1) at the auxiliary/supplementary heater coolant pipes and disconnect the coolant hoses. [Note: Make sure that coolant can only escape from the auxiliary/supplementary heater and that the coolant circuit to the heat exchanger in the front air conditioning unit remains full, so that only the auxiliary/supplementary heater has to be bled following installation .]
14. Unfasten the clamps (2) and disconnect and seal the fuel line. If necessary, replace the clamps with screw clamps or clamps of the same type and secure these using suitable pliers Electronic parts catalogue.
15. ⚠ Observe the applicable rules for cleanliness, take the appropriate precautions and heed the relevant safety measures when working on open fuel systems Fuel supply system20. — Unfasten the clamp (2) and separate the exhaust system .
16. Unfasten the holder for the coolant and exhaust pipe.
17. Unscrew the nuts (2) and screw out the bolts (1).
18. Screw out the bolts (1).
19. Unfasten the auxiliary/supplementary heater holder.
20. Screw out the bolts (1).
21. Disengage the auxiliary/supplementary heater holder upwards (arrow).
22. Take out the auxiliary/supplementary heater with holder.

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