Intake Air System, Checking For Leaks (False/Unmetered Air)

Checking with engine leak detector spray G 001 800 A1

NOTE:
- The vacuum in the intake system will cause the leak detector spray to be drawn in with the unmetered air. The leak detector spray reduces the ignitability of the mixture. This leads to a drop in engine speed and to a change of Oxygen Sensor (O2S) reading.
- The safety precautions listed on the container must be adhered to.

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required







- VAG 1551 Scan tool (or VAG 1552) with VAG 1551/3 adapter cable

NOTE: All functions which could previously be performed with VAG 1551/1552 can also be performed with the VAS 5051.

- Engine leak detector spray G 001 800 A1

Test sequence
- Connect VAG 1551 Scan tool (or VAG 1552) and select engine electronics control module with the "Address word" 01. When doing this the engine must be running at idle speed.

Indicated on display:


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- for function "Read measured value (data) block" and confirm entry with -Q- button.

Indicated on display:


Read measured value block
Input display group number XXX


- Press buttons -0-, -0- and -1- for "Display group number 1" and confirm entry with -Q- button.

Indicated on display: (1...4 = display zones)


Read measured value block 1 ->
1 2 3 4


- Check whether the Engine Coolant Temperature (ECT) is above 85 degrees C in display zone 2.
- Observe the engine speed in display zone 1 and the Oxygen Sensor control before Three Way Catalytic Converter (TWC) in display zones 3 and 4.
- Observe the engine speed in display zone 1 and the Oxygen Sensor control before Three Way Catalytic Converter (TWC) in display zone 3.
- Systematically spray parts of the intake system with engine leak detector spray.

If the engine speed or the Oxygen Sensor control do not change:
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.

If the engine speed drops or the Oxygen Sensor control changes:
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.
- Check sprayed areas of intake system for leaks and rectify if necessary.