Removing and installing fuel system diagnostic pump (CBTA, CBUA) — VW
Removing and installing fuel system diagnostic pump (CBTA, CBUA) on VW: 9 steps, engines CBTA, CBUA. What to remove, in what order, and what to check.
On the Golf VI (5K, 2008–2013) and the cars coded 521 with the CBTA and CBUA five-cylinder petrol engines, the fuel system diagnostic pump (the evaporative leak-check pump) lives behind the rear right wheel housing liner. Getting to it means removing the rear right wheel and the liner. The pump is then freed by detaching the vacuum line, unplugging the electrical connector, releasing the breather line with its release button and taking off the retaining nuts, after which it unhooks complete with its bracket. It is a short job; what matters is reconnecting each of the three lines to the correct port and making sure the breather and vacuum connections are fully latched, since a loose line will simply set a leak fault again.
🧭 Before you start
The rear right wheel and wheel housing liner come off to expose the pump. Vacuum line, electrical connector and breather line are disconnected, the nuts are removed and the pump is unhooked with its bracket. Installation is the reverse, finishing with the liner and wheel refitted.
Fits: VW Golf VI (5K, 2008–2013); platform code 521
Don't miss
- Note which line goes where before disconnecting the vacuum and breather lines.
- Press the release button on the breather line; do not pull it off by force.
- Confirm every line clicks home, as a loose connection will trigger a leak fault.
- Tighten the wheel bolts to the specified torque when refitting the rear right wheel, as general workshop practice.
Written for this job from the workshop steps below · TorqFix editorial.
📋 Procedure
- Remove rear right wheel Running gear, axles, steering44Wheels, tyres and alignment.
- Remove rear right wheel housing liner General body repairs, exterior66Wheel housing liner; Removing and installing wheel housing liner.
- Detach vacuum line (1).
- Release and pull off electrical connector (2).
- Press release button and pull off breather line (3).
- Remove nuts (arrows).
- Unhook diagnosis pump with bracket.
- Install rear right wheel housing liner General body repairs, exterior66Wheel housing liner; Removing and installing wheel housing liner.
- Fit rear right wheel Running gear, axles, steering44Wheels, tyres and alignment.
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- Adjusting valve timing – VW Passat B5 · 83 torque figures
- Removing and installing camshafts – VW Passat B6 · 39 torque figures
- Removing and installing coolant pump · 53 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.