Checking fuel-driven supplementary heater — AUDI
Checking fuel-driven supplementary heater on Audi: factory workshop procedure. Full factory text, tools and checks.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📋 Procedure
Checking fuel-driven supplementary heater
Note
Vehicles with a diesel engine (all except vehicles with 6-cyl. TDI engine as of Model Year 2009 conforming to a certain emissions standard and not provided with an auxiliary heater as optional extra) are currently fitted with a fuel-driven supplementary heater. Activation of the supplementary heater causes heat energy to be supplied to the engine coolant in the event of a request from the front operating and display unit,
Climatronic control unit
J255
.
Auxiliary/supplementary heater
Rep. gr.
82
.
On vehicles with a diesel engine (all except vehicles with 6-cyl. TDI engine as of Model Year 2009 conforming to a certain emissions standard) and fitted with an
“auxiliary heater”
as optional extra, the auxiliary heater assumes this function and operates as a fuel-driven supplementary heater
Auxiliary/supplementary heater
Rep. gr.
82
.
Checking of auxiliary/supplementary heater actuation is described in the air conditioner guided fault-finding routine
"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
The measured value block of the front operating and display unit,
Climatronic control unit
J255
shows that the auxiliary/supplementary heater is being actuated or indicates why there is no actuation in spite of a corresponding request
"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
The same conditions essentially apply to actuation of the fuel-driven supplementary heater (or the auxiliary heater as supplementary heater) as to actuation of the
supplementary air heater element
Z35
Chapter
and
Auxiliary/supplementary heater
Rep. gr.
82
From model year 2011 onwards, a start/stop system (optional equipment) is offered for this vehicle in combination with certain engines. On vehicles with a start/stop system and auxiliary/supplementary heater, pay attention to the correct version, encoding and adaption of the auxiliary/supplementary heater (
supplementary heater control unit
J364
)
Electronic parts catalogue
and
"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051
.
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
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The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.