Checking operation of fuel shut-off valve N109 — AUDI
Checking operation of fuel shut-off valve N109 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 operation of
fuel shut-off valve
N109
Note
Not all auxiliary heater versions are fitted with a
fuel shut-off valve
N109
B
. Currently it is only planned for the auxiliary heater version for vehicles with diesel engine with part number 1K0 815 005 from index
“HD”
onwards and with software number from
“0100”
onwards
Chapter
(introduction not yet finalised)
Electronic parts catalogue
.
The installation of a
fuel shut-off valve
N109
is currently only planned for vehicles with diesel engine (only installed on VW vehicles; introduction for Audi vehicles not yet finalised)
Electronic parts catalogue
Currently no auxiliary heater with a
fuel shut-off valve
N109
is installed in Audi A3 vehicles during production (introduction not yet finalised). However it is possible that individual vehicles have been retro-fitted with an auxiliary heater with a
fuel shut-off valve
N109
; therefore it is important to pay attention to the correct version.
Detach fuel pipe from auxiliary heater
Chapter
.
Note
Seal the fuel pipe detached or place the end of the detached fuel pipe in a small vessel (a small amount of fuel may emerge during subsequent final control diagnosis).
Connect e.g.
vacuum hand pump
VAS 6213
to fuel pipe to auxiliary heater
A
.
With ignition switched off, connect
vehicle diagnostic, testing and information system
VAS 5051 A
to 16-pin diagnostic socket in vehicle using
diagnosis cable
VAS 5051/5A
and select function
“Final control diagnosis of auxiliary/additional heater”
Guided Fault Finding function of
vehicle diagnostic, testing and information system
5051 A
.
Use the
vacuum hand pump
VAS 6213
to build up a pressure of approx. 1.5 bar in the fuel pipe to the auxiliary heater.
Wait approx. 1 minute. The pressure must be maintained.
Perform final control diagnosis for auxiliary/additional heater
Guided Fault Finding function of
vehicle diagnostic, testing and information system
5051 A
. When doing so, keep switching until control element
fuel shut-off valve
N109
is displayed.
Activate the
fuel shut-off valve
N109
control element and in doing so observe the display on the pressure gauge of the
vacuum hand pump
VAS 6213
.
As soon as the
fuel shut-off valve
N109
is activated, the pressure in the fuel pipe must be released (via the
fuel shut-off valve
N109
).
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.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.