Evaporative Emissions (EVAP) System, Function Checking

Evaporative Emissions (EVAP) System, Checking

Function, checking

- Connect VAG1551 or VAG1552 Scan Tool (ST), and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (engine running at idle). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG1551 or VAG1552 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
Input display group number XXX


- Press buttons -0-, -1- and -2- to input display group number 12 (012), and press -Q- button to confirm input.

Indicated on display


Read Measuring Value Block 12 ->
1 2 3 4


- Check specified values for function of EVAP system at idle (display fields 1-4):







Check display field 4:
"EVAP active" = EVAP system operational
"EVAP inact." = engine cold
"lambda-Adaptation" = no EVAP system operation, oxygen sensor control learning

Check display field 2:
-5% = EVAP system leaking, or no fuel vapors in EVAP canister
95% = EVAP canister saturated
100% = EVAP system blocked

- Press -> button to advance program sequence.
- Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.