Removing and installing energy management control unit J644 - vehicles up to model year 2008 — AUDI
Removing and installing energy management control unit J644 - vehicles up to model year 2008 on Audi: factory workshop procedure.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📋 Procedure
Removing and installing energy management control unit
J644
- vehicles up to model year 2008
Special tools and workshop equipment required
Removal lever
80 - 200
Removing
Note
Charger must NOT be connected during removal and installation.
When renewing control unit select
“Replacement” function for appropriate control unit in
“Guided Fault Finding” or
“Guided Functions” vehicle diagnostic tester. (repair group 72).
Switch off ignition and take out ignition key.
Remove bolt (2) and lift out footwell vent (1).
Release retaining clips on rear of cover (1) in direction of arrows (A).
Then remove cover from driver's seat bracket in direction of arrow (B).
Pry cover (1) out of floor covering using removal lever
80 - 200.
Lift floor covering (2) slightly in the vicinity of earth cable.
Unscrew nut (3) and detach earth cable (4) from earth point.
Pry covers (1) and (3) out of floor covering using removal lever
80 - 200.
Pry cover (3) out of floor covering using removal lever
80 - 200.
Remove two front bolts (1) from driver's seat bracket and tilt seat bracket (2) upwards.
Unplug the electrical connector (5) by releasing catch and pivoting the retaining clip.
Detach earth cable (3) leading to battery from energy management control unit
J644.
First unscrew cap nut (4) then cap nut (1).
Remove the energy management control unit
J644 item 2.
Installing
To ensure the correct function of energy management control unit
J644 it is important to keep to the following sequence during installation:
Secure energy management control unit
J644 item 2 to body by screwing in and tightening cap nut (1).
Tighten cap nut (4).
Secure earth cable (3) to battery at energy management control unit
J644.
Plug in electrical connector (5) at energy management control unit
J644.
Connect earth cable to battery.
Perform measures required after connecting battery. (repair group 72).
After renewing energy management control unit
J644
, it must be re-encoded in
“Guided Fault Finding” or
“Guided Functions” mode vehicle diagnostic tester.
Tightening torques
Component
Nm
Control unit to body (20)
Earth cable to control unit (20)
Footwell vent to battery cover (2)
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 → · How these pages are made →Workshop data on this page last updated 20 Sep 2026.