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

Checking with engine leak detector spray G 001 800 A1

Special tools and equipment
- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable
- Engine leak detector spray G 001 800 A1

Test conditions
- Coolant temperature must be at least 80 °C, See display group 04, display zone 3.

Test sequence


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 reading.
- The safety precautions listed on the container must be adhered to.


- Connect VAG1551 scan tool (VAG1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine must be running at idling speed. (Connecting scan tool and selecting engine control module). Refer to "VAG1551 Scan Tool Tools and Equipment

Indicated on display:


Rapid data transfer HELP
Select function XX


- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

Indicated on display:


Read measured value block HELP
Input display group number XXX


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

Indicated on display:(1 to 4 = Display zones)


Read measured value block 1 ->
1 2 3 4


- Observe the engine speed in display zone 1 and the oxygen sensor control in display zone 3.
- Systematically spray parts of the intake system with engine leak detector spray.

If the engine speed drops or the oxygen sensor controller changes:
- Press -> key.
- Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
- Switch ignition off.
- Check sprayed areas of intake system for leaks and repair if necessary.