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

Intake 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:
- 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. Connecting VAS 5051/VAG1551 Scan Tool
- Engine must run at idle for this.

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.

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 to 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 problem.