Checking low pressure on high-pressure pump, engines with supplementary fuel pump V393 — AUDI
Checking low pressure on high-pressure pump, engines with supplementary fuel pump V393 on Audi: 13 steps, engines CAAA, CAAB, CAAC, CFCA.
Workshop procedure for AUDI — the exact step sequence and torque figures, straight from real workshop data.
🧭 Before you start
Fits: platform codes SF, SG
- Special tools named: VAS 6551
Don't miss
- Ensure that drain tap (C) on pressure testerVAS 6551(1) is closed.
📐 31 workshop diagrams for CAAA
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
- ⚠ Read rules for cleanliness and the instructions when performing any work on the fuel system.Always follow these rules for cleanliness and instructions before starting work and while working on the fuel system.Wrap a clean cloth around the connection before opening the fuel system, then carefully loosen the connection to release the pressure. — Loosen spring-type clip(arrow) of fuel supply line (1).
- Pull off fuel supply line (1) from high-pressure pump (2).
- Collect escaping fuel with a cleaning cloth.
- Insert connection fittingVAS 6551/5-1 into fuel supply line (1) and secure it with a clip.
- Connect hoseVAS 6551/2 between connecting nippleVAS 6551/5-1 and connection point (A) of pressure tester (diesel)VAS 6551.
- Connect hoseVAS 6551/5-2 between connection (B) of pressure tester (diesel)VAS 6551 and high-pressure pump (2).
- Secure hoseVAS 6551/5-2 to high-pressure pump (2) with a clip.
- Switch on pressure testerVAS 6551 by pressing On/Off button.
- Ensure that drain tap (C) on pressure testerVAS 6551(1) is closed.
- Shut-off valves (A) and (B) on pressure testerVAS 6551(1) are open.
- Connect to test instrument boxVAS 6356.
- Activate fuel pump using guided function "“Fuel pump activation”".
- The fuel pump is activated.
Ask TorqFix about your Audi CAAA — it answers with the exact sequence for that engine and the workshop drawing for each step. First question is free after a 20-second sign-up, no card.
Ask about your Audi CAAA — free → or sign up free to see the drawingsOther AUDI procedures
- Removing and installing fuel tank, engine codes CAAA, CAAB, CAAC, CAAD, CAAE, CCHA, CCHB, CFCA
- Removing and installing Hall sender G40
- Removing and installing camshaft oil seal – Audi TT Mk2
- Removing and installing fuel delivery unit, fuel gauge sender
- Removing and installing tandem pump, engine codes AXB, AXC, BRR, BRS
- 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.