Test sequence
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- Connect Scan Tool VAG 1551 or Vehicle system tester VAG1552/. Start engine and select "Address word" 01 of engine control module. → 01 ON BOARD DIAGNOSTIC (OBD)
Indicated on display
| Rapid data transfer HELP Select function XX |
- Press keys "0" and "4" for function "Initiate basic setting" and confirm entry with "Q" key.
Indicated on display
| Basic setting Input display group number XXX |
- Press keys "0" , "7" and "1" for "Display group number 71" and confirm entry with "Q" key.
NOTE:
- The engine must not be loaded during this diagnosis, if this occurs the diagnosis will be interrupted and will not start again until the engine is revved-up.
Indicated on display (1...4 = display zones)
| System in basic setting 71 -> 1 2 3 4 |
If "Read op." appears in display zone 1:
- Open fuel tank filler cap briefly to release pressure in fuel tank. This will close reed contact.
If the diagnosis is initiated by the engine control module the display in display zone 4 jumps from "Test OFF" to "Test ON".
NOTE:
- If the display in display zone 4 jumps from "Test ON" to "Test OFF" during the diagnosis, repeat the diagnosis. When repeating the diagnosis test, the diagnosis can take up to 60 seconds before the display in display zone 4 jumps from "Test OFF" to "Test ON".
- Leave engine running at idling speed until display zone 4 displays specification "Syst. OK.".
If "Sys. OK." appears in display zone 4:
- Press → key.
- Press keys "0" and "6" for function "End output" and confirm entry with "Q" key.
- Switch ignition off.
If "Sm leak or La leak" appears in display zone 2 and "Sys. n.OK." appears in display zone 4:
- Press → key.
- Check DTC memory: → 01 ON BOARD DIAGNOSTIC (OBD)
- Read readiness code: → 01 ON BOARD DIAGNOSTIC (OBD)
- Generate readiness code again if DTC memory has been erased or engine control module separated from permanent positive supply: → 01 ON BOARD DIAGNOSTIC (OBD)
If no DTC is stored in DTC memory:
- Press keys "0" and "6" for function "End output" and confirm entry with "Q" key.
- Switch ignition off.
- Check that fuel tank cap is completely closed or if seal is leaking, replace as necessary.
- Repeat functional check.
If fault is still present:
- Check that fuel delivery unit union nut is tight or if seal is leaking replace as necessary, → Fuel delivery unit , removing and installing , Removing and installing fuel delivery unit.
- Repeat functional check.
If fault is still present:
- Remove rear right wheel housing liner: → 66 EXTERIOR EQUIPMENT
- Check to see if pressure hose between LDP and EVAP canister is leaking, - - and replace if necessary.
- Check lines and line connections between EVAP canister and fuel tank flap unit or tank breather valve for leaks → EVAP canister system, assembly overview , Assembly overview of EVAP system.
- Repeat functional check.
If fault is still present:
- Remove EVAP canister and check for cracks and leaks, replace if necessary → Components of the EVAP system, servicing , Servicing components of EVAP system.
- Repeat functional check.