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

Intake air system, checking for leaks

Required special tools and test equipment
- VAG 1551 or VAG 1552 Scan Tool (ST) with VAG 1551/3 adapter cable
- Engine leak detector spray G 001 800 A1


CAUTION:
Part numbers are listed here for reference only. Always check with your Parts department for the latest information.


NOTE:
- If there are leaks, intake manifold vacuum will draw in the leak detector spray with outside air. The spray reduces the ability of the fuel/air mixture to ignite, which causes a drop in engine speed and a significant increase in CO-content.
- Observe the safety precautions listed on the container.

Checking
- Connect VAG 1551 or VAG 1552 scan tool and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine running at idle).Refer to "Scan tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551/VAG 1552 Scan Tool" Testing and Inspection

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.

Indicated on display


Read Measuring Value Block HELP
Input display group number XXX


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

Indicated on display (1-4 display fields)

Read Measuring Value Block 1 ->
1 2 3 4

- Monitor oxygen sensor control in display fields 3 and 4.

Display Group 1:

- Systematically spray parts of intake air system with engine leak detector spray.

If engine speed drops, or the values displayed for oxygen sensor control change:
- Check for leaks in area of intake air system most recently sprayed, and eliminate leaks.