Fuel Delivery and Air Induction: Testing and Inspection
Intake Air System (Unmetered Air), Checking For Leaks
Checking with engine leak detector spray G001 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 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.
Special tools, test equipment and auxiliary items
- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable
- Engine leak detector spray G 001 800 A1
Test conditions
- Engine Coolant Temperature (ECT) must be at least 80°C, see display group 04, display zone 3.
Test sequence
- Connect VAG1551 scan tool (or VAG1552). Start engine and select "Address word" 01 of Motronic Engine Control Module (ECM) -J220-. 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 to 4 = Display zones)
Read measuring value block 1 ->
1 2 3 4
- Check whether Engine Coolant Temperature (ECT) is above 80°C in display zone 2.
- Observe engine speed in display zone 1 and oxygen sensor control before Three Way Catalytic Converter (TWC) in display zone 3.
- 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 function "End output" and confirm entry with -Q- button.
- Switch off ignition.
- Check sprayed areas of intake system for leaks and repair if necessary.
If the engine speed and the oxygen sensor control do not change:
- Press -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Switch off ignition.