Functional Check

EVAP Canister, Checking

Special tools and equipment
- V.A.G 1551 Scan Tool or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Checking conditions







- Fuse 29 must be OK.
- No codes stored in DTC memory
- All electrical consumers, e.g. lights and rear window defogger must be switched off
- Air conditioner must be switched off.
- Intake air temperature less than 90 °C See display group 04, display field 4
- Coolant temperature less than 95 °C See display group 04, display field 3

Functional check
- Connect V.A.G 1551 (V.A.G 1552). Start engine and select engine electronics control module with "Address word" 01.


Indicated on display


Rapid data transfer HELP
Select function XX


- Press -0- and -8- buttons to select "Read measured value block" and confirm entry with -Q- button.


Indicated on display


Read Measuring Value block HELP
Input display group number XXX


- Press -0-, -7- and -1- to select "Display group number 71" and confirm entry with -Q- button.


Indicated on display


Read measured value block 71 ->
Reed closed Test OFF

- Press button -4- to select "Introduction of basic setting" function.


Indicated on display


System in basic setting 71 ->
Reed open Test ON


Indicated on display


System in basic setting 71 ->
Reed closed Test ON


The test of the EVAP system will be initiated. The function of the Reed contact (in the Leak Detection Pump - V144-) will be checked by the control module.


Indicated on display


System in basic setting 71 ->
Reed open Syst.Test Test ON



After approx. 30 seconds the LDP - V144- will be activated and build up pressure in the fuel system.


Indicated on display


System in basic setting 71 ->
Reed open Syst.Test Test ON



The test will be initiated after approx. 45 seconds (when there is sufficient pressure available in the fuel system).


Indicated on display


System in basic setting 71 ->
Reed open Check Test ON


The Leak Detection Pump (LDP) - V144- switches off and the ECM measures the time until the Reed contact closes.


Indicated on display


System in basic setting 71 ->
Reed closed Check.END Syst.OK



- Check display in display fields 3 and 4.

If the specifications are not attained:
- Check system for leaks. Leak Check Notes

If the specifications are obtained:
- Press -> button.


Indicated on display


Rapid data transfer HELP
Select function XX


- Press -0- and -6- to select "End data transfer" function and confirm input with the -Q- button.