Checking the Intake System for Leaks (Unmetered Air): VW 2.3 (AGL)
Step-by-step checking the Intake System for Leaks (Unmetered Air) for the VW 2.3 (AGL): factory workshop text.
Workshop procedure for VW — the factory write-up, straight from real workshop data.
🔧 Engine codes this applies to
📋 Procedure
Check using engine leak search spray G 001 800 A1
Special tools, testing and measuring devices, etc. required
Fault output device V.A.G 1551 with cable V.A.G 1551/5
Engine leak search spray G 001 800 A1
Testing condition
Coolant temperature at least 80 °C
Testing Procedure
Notes:
The vacuum in the intake system draws in the leak search spray with the unmetered air. The leak search spray lowers the inflammability of the mix. This leads to a drop in engine speed and to a change in the lambda sensor value.
The safety instructions printed on the can must be followed.
Connect the fault output device V.A.G 1551 and use the "Address word" 81 to select the control unit for engine electronics. Here, the engine must be idling.
(Connect V.A.G fault output device and select the control unit for engine electronics => Page
01-5
.)
LT Diagnosis
HELP
Select function XX
Display:
Press the keys 0 and 8 for the function "Read measurement value block" and confirm the input using the Q key.
Read measurement values block
HELP
Enter display group number XXX
Display:
Press the keys 0;0 and 4 for the "Display group number 004" and confirm the input using the Q key.
Read measurement values block 4
⇒
1
2
3
4
Display:
(1...4 = display fields)
Only continue the test when:
the coolant temperature is at 80 °C
-display field 2-
Observe the value of the lambda control in display field 3. The display must be in the range between
-10.0...10.0 %.
Systematically spray the parts of the intake system with engine leak search spray.
If the engine speed or the value of the lambda control does not change:
Press the ⇒key.
Press the keys 0 and 6 for the function "Quit output" and confirm the input using the Q key.
If the engine speed drops or if the value of the lambda control in display field 3 is no longer in the range between
-10.0...10.0 %:
Press the ⇒key.
Press the keys 0 and 6 for the function "Quit output" and confirm the input using the Q key.
Check the sprayed area of the intake system for leaks and remedy the fault.
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.
Ask about my car →Other VW procedures
- Checking intake manifold pressure sender
- Checking the Ignition Transformer – VW 2.3 AGL
- Checking the Coolant Temperature Sender – VW AGL/AUH
- Checking the Operating States of the Engine – VW 2.3 AGL
- Checking the Intake Air Temperature Sender – VW 2.3 AGL
- Removing engine · 41 torque figures
- Removing and installing camshaft – VW Golf Cabriolet · 47 torque figures
- 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.