Checking Intake Air System For Leaks (Unmetered or False Air)

Intake Air System, Checking For Leaks (Unmetered Air)

Special tools and equipment







- VAS5051 with VAG5051/1
or
- VAG1551 with VAG1551/3B
- Engine leak detection spray G 001 800 A1


NOTE:
- The negative pressure in the intake system sucks in the leak detection spray with the unmetered air. Leak detection spray decreases ignition quality and performance of the fuel mixture. This causes a reduction in engine speed and a sharp increase of CO content.
- It is absolutely necessary to follow the safety precautions listed on the can.

Test Sequence
- Connect VAS5051 tester or VAG1551 scan tool and select the control module for engine electronics using "address word" 01. Refer to "Scan Tool Testing/Scan Tool Connecting And Initial Checks", Testing and Inspection

Engine must run at idle for this.

When indicated on display:


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read Measuring Value Block" and press -Q- button to confirm input.

When indicated on display:


Read Measuring Value Block Q
Input display group number XXX


- Press buttons -0-, -0- and -1- to select "display group number 001" and press -Q- button to confirm input.

Indicated on display: (1 thru 4 = display fields)


Read Measuring Value Block 1 ->
1 2 3 4


- Make note of engine speed in display field 1.
- Spray intake system parts with engine leak detection spray in a systematic manner.

If engine speed does not change:
- Press -> button.

Indicated on display (function selection):


Rapid data transfer HELP
Select function XX


If engine speed decreases:
- Press -> button.
- Press buttons -0- and -6- to select "End output" and press -Q- button to confirm input.
- Switch ignition off.
- Check sprayed part of intake system for leaks, and eliminate the error.