Replacing diesel direct injection system control unit 2J494 — AUDI
Replacing diesel direct injection system control unit 2J494 on Audi: 16 steps, engines AKF. What to remove, in what order, and what to check after.
Workshop procedure for AUDI — the exact step sequence and torque figures, straight from real workshop data.
🧭 Before you start
Fits: Audi A8 D2 (4D)
Don't miss
- Connect up fault reader and select vehicle system "“11 - Engine electronics 2”" from list. When doing this, the ignition must be switched on.
- Always start by displaying and printing out the control unit identification.
- On vehicles fitted with cruise control (can be seen from steering column switch), this must be activated in the engine control unit.
🔧 Engine codes this applies to
📋 Procedure
- Connect up fault reader and select vehicle system "“11 - Engine electronics 2”" from list. When doing this, the ignition must be switched on.
- Always start by displaying and printing out the control unit identification.
- Slacken off cross-head bolts (1) at electronics box in plenum chamber.
- Unclip plenum chamber cover (2) at front at bulkhead (arrows).
- Detach plenum chamber cover.
- Prise out cover (1) in scuttle panel trim and slacken off rear cross-head bolt (arrow) at rear right.
- Slacken off the remaining cross-head bolts (arrows).
- Detach cover of electronics box in plenum chamber.
- Screw out bolt (arrow).
- Disengage retainer.
- Release and unplug connectors of diesel direct injection system control unit 2J494"“Item 2”".
- Take out old diesel direct injection system control unit 2J494"“Item 2”" and install new engine control unit.
- The immobilizer does “not” have to be adapted to diesel direct injection system control unit 2J494.
- Interrogate fault memory and erase if necessary.
- Encode new engine control unit .
- On vehicles fitted with cruise control (can be seen from steering column switch), this must be activated in the engine control unit.
Other AUDI procedures
- Checking exhaust gas recirculation valves N18 and N213
- Checking glow plugs · 2 torque figures
- Checking intake manifold pressure sender G71 – Audi A8 D2
- Checking operation – Audi Q7
- Checking accelerator position sender G79
- Removing and installing toothed belt – Audi · 56 torque figures
- Removing engine – Audi A8 D3 · 41 torque figures
- Removing camshaft timing chain from camshafts – Audi A6/A7 C7 · 38 torque figures
- Installing engine – Audi A8 D4 · 36 torque figures
- Removing and installing camshaft timing chain · 29 torque figures
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.