Canister Purge Control Valve: Testing and Inspection

Evaporative Emission (EVAP) Canister Purge Regulator Valve, Checking

In a no-current situation the solenoid valve is closed.

Checking activation:

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required







- V.A.G 1551 scan tool


NOTE: The vehicle system tester V.A.G 1552 can be used instead of the VAG 1551 scan tool, however a print-out is not possible.







- V.A.G 1551/3 Cable

Test conditions
- Coolant temperature must be at least 80 °C, See display group 04, display zone 3.







- Fuse No. 43 must be OK.

Functional check
- Connect VAG 1551 scan tool ((V.A.G 1552). Start engine and select the engine control module with the "Address word" 01. Connecting scan tool and selecting engine control module:

Indicated on display:


Rapid data transfer HELP
Select function XX


- Press keys 0 and 8 for the "Read measured value block" function and confirm entry with Q key.

Indicated on display:


Read measured value block
Input display group number XXX


- Press keys 0, 7 and 0 for "Display group number 70" and confirm entry with Q key.

Indicated on display: (1 to 4 = Display zones)


Read measured value block 70 ->
1 2 3 4


- Press key 4 for the "Basic setting" function ("Tank venting valve diagnosis" will be initiated)


NOTE: The engine must not be loaded during this diagnosis because the diagnosis will be interrupted and will not be started again until the engine is revved-up.


Indicated on display: (1 to 4 = Display zones)


System In basic setting 70 ->
1 2 3 4


When the diagnosis is initiated by the engine control module, the display in display zone 4 jumps from "Test OFF" to "Test ON"
- Run engine at idling speed until the specification "TBV OK" is displayed in display zone 4.


NOTE: TBV stands for tank breather valve (Evaporative Emission (EVAP) canister purge regulator valve).


If "TBV not OK" appears in display zone 4:
- Initiate the Output Diagnostic Test Mode and activate the Evaporative Emission (EVAP) canister purge regulator valve (N80):
- Check DTC memory:
- Read out readiness code:
- If the DTC memory has been erased or the engine control module separated from the permanent positive, the readiness code must be generated again.

If the specification "TBV OK" is obtained:
- Press -> key.

Indicated on display:


Rapid data transfer HELP
Select function XX


- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off ignition.