Intake Air System, Checking For Leaks (Unmetered Air)

Intake Air System, Checking For Leaks (Unmetered Air)

Checking with engine leak detector spray G 001 800 A1

Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester V.A.G 1552 with cable VAG 1551/3B
- Engine leak detector spray G 001 800 A1

Test conditions
- Coolant temperature at least 85 °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 combustibility 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 scan tool VAG 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. 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 Measuring Value Block" and confirm entry with Q button.

Indicated on display


Read Measuring 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 Measuring Value Block 1 ->
1 2 3 4


- Observe engine speed in display zone 1 and oxygen sensor control before catalyst in display zone 3.
- Check whether coolant temperature is above 85 °C in display zone 2.
- Systematically spray parts of intake system with engine leak detector spray.

If the engine speed drops or the oxygen sensor control changes:
- Press -> button.
- Press buttons 0 and 6 for "End data transfer" function and confirm input with Q button.
- Switch ignition off.
- Check sprayed areas of intake system for leaks and repair if necessary.
- Erase DTC memory to put learned values in a neutral setting, checking and erasing learned values. Reading Diagnostic Trouble Codes