Removing and installing auxiliary heater (all models except Audi S6) — AUDI

🧭 Before you start

Read J364 encoding first, switch everything off, then remove the bumper cover, left headlight and, on diesels, the charge air cooler. Clamp and disconnect coolant hoses, intake hose, fuel pipe and connectors, remove the bolts and exhaust fixing, and take out the heater. On refit, check routing and the exhaust gasket, fill and bleed coolant, then encode, clear faults, run pipe-filling and basic settings, and run the heater at full load for at least ten minutes.

Fits: Audi A6 C6 (4F, 2004–2011)

• Special tools named: VAS 5051

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• Read J364 encoding and configuration before removal so the replacement can be set the same.
• Fit the correct heater version for petrol or diesel, including the right metering pump V54.
• Exhaust pipe must protrude down through its gasket; nothing may touch the exhaust, coolant, fuel pipe or wiring.
• Write the year of initial commissioning on the heater rating plate and duplicate plate after replacement.
• Run the heater at full load for at least ten minutes to bleed the fuel pipe and burn off lubricant.

Written for this job from the workshop steps below · TorqFix editorial.

📋 Procedure

1. Before replacing the auxiliary heater, interrogate encoding and configuration of auxiliary heater control unit J364 in "“Control unit replacement”" function of vehicle diagnostic, testing and information systemVAS 5051 A in "Guided fault-finding" function .
2. Switch off the ignition and the auxiliary heater.
3. Remove front bumper cover General body repairs, Exterior63.
4. Remove left headlight Electrical System94.
5. If applicable, remove the charge air cooler (e.g. on vehicles with diesel engine) Engine, mechanics21.

6. Clamp off both coolant hoses (A) and (B) using hose clamps3094.
7. Disconnect coolant hoses (A) and (B) and air intake hose (C).
8. Detach fuel pipe (C) from angle hose.
9. Unplug connectors (B).
10. Remove bolt (A).
11. Clamp off coolant hose (B) using hose clamps3094 .
12. Disconnect coolant hose from auxiliary heater.
13. Remove bolt (A).
14. Remove bolt (arrow) for exhaust pipe.
15. Unscrew nut (arrow) and remove the auxiliary heater. [Note: The illustration shows an exhaust silencer with corrugated exhaust pipes not fitted with a heat shield. If not already provided, fit the exhaust silencer with a new heat shield Electronic parts catalogue.] [Note: Pay attention to correct assignment of the auxiliary heater. Depending for example on the auxiliary heater version (with or without fuel shut-off valve N109), vehicles with a diesel engine have to be fitted with different types of metering pump V54 and Electronic parts catalogue.A fuel shut-off valve N109 is currently only provided for the diesel version; gradual introduction as of 05.2008 Electronic parts catalogue.]
16. Following installation, check the exhaust pipe, coolant hoses, fuel pipe and wiring to the auxiliary heater (must not make contact with other components).
17. After installing noise insulation, check position of exhaust pipe (A); a gasket (B)must be installed between exhaust pipe (A) and noise insulation. Exhaust pipe must protrude downwards out of gasket and outlet of exhaust gas from exhaust pipe (A) must not be impeded [Note: On replacement, pay attention to correct auxiliary heater version (different design for vehicles with petrol or diesel engine) .Secure all hose connections with standard clamps Electronic parts catalogue.If the auxiliary heater has been replaced, enter the year of initial commissioning for the newly installed auxiliary heater on the heater rating plate and the new "“duplicate rating plate”".]
18. Top up coolant Engine, mechanics19.
19. Bleed the coolant circuit and Engine, mechanics19.
20. Depending on the nature of the repair work, the following checks/settings may have to be made after installing the auxiliary heater :
21. If the assignment of the supplementary heater control unit J364 (rating plate) differs from that indicated on the display of the vehicle diagnostic, testing and information systemVAS 5051 A, check the display "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
22. Check encoding of auxiliary heater control unit J364 or enter encoding vehicle diagnostic, testing and information systemVAS 5051 A "Guided fault-finding" function .
23. Interrogate fault memory of auxiliary heater control unit J364 and delete any displayed faultsvehicle diagnostic, testing and information systemVAS 5051 A in "Guided fault-finding" function.
24. Check operation of the auxiliary heater remote control and perform basic setting of the supplementary heater control unit J364 if necessary Vehicle diagnostic, testing and information systemVAS 5051 A, "Guided fault-finding" function.
25. If the auxiliary heater is replaced together with the supplementary heater control unit J364, check the operation of at least one hand transmitter and re-adapt all hand transmitters if necessary (remote control hand transmitter adaption) and Vehicle diagnostic, testing and information system5051 A, "Guided fault-finding" function.
26. Interrogate the adaption of the supplementary heater control unit J364 and if necessary enter the adaption value "“5”" in the adaption channel "“Pipe filling”" (if a value other than "“0”" is displayed) Vehicle diagnostic, testing and information systemVAS 5051 A, "Guided fault-finding" function.
27. If the value displayed in the "“Pipe filling”" adaption channel was other than "“0”", perform the "“Basic setting”" function, "“Pipe filling”" display group (the metering pump V54 is actuated for the time set in the "“Pipe filling”" adaption channel, the adaption in the "“Pipe filling”" adaption channel is reset to "“0”" and the "“Pipe filling”" fault is erased) "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
28. Start the engine and interrogate the fault memory of all control units fitted (faults may also have been entered for other control units by way of the convenience data bus system) Vehicle diagnostic, testing and information systemVAS 5051 A, "Guided fault-finding" function.
29. Perform the "“Basic setting”" function to switch on the auxiliary heater. After the auxiliary heater has been operated once in heating mode in the "“Basic setting”" function, certain displays in the "“Measured value block”" switch from "“not OK”" to "“OK”""Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
30. Switch on the auxiliary heater and check and if necessary re-adjust the CO2 content in the auxiliary heater exhaust gas (if for example the control unit J364 has been replaced together with the combustion air blower V6) .
31. After replacing auxiliary heater components, switch on the auxiliary heater before handing over the vehicle to the customer and allow the auxiliary heater to run for at least 10 minutes in full load mode. There may still be remnants of factory lubricant for example in the components and these would evaporate following initial activation as soon as the components become hot.
32. After removing and installing fuel system components or the auxiliary heater, the auxiliary heater is to be switched on and operated at full load for at least 10 minutes to ensure complete bleeding of the fuel pipe.

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