Exhaust Gas Recirculation: Testing and Inspection

Special Tools, Testers And Auxiliary Items
- US 8012 Hand vacuum pump
- VAG 1551 Scan Tool or VAG 1552 Scan Tool with VAG 1551/3 adaptor cable

Checking Conditions
- Vacuum lines and hose connections leak-light
- Vacuum lines not blocked/kinked
- Engine oil temperature 50°C minimum

Test Sequence
- Connect VAG 1551 Scan Tool (VAG 1552) and select "address word 01" engine electronics with engine idling

Rapid data transfer HELP
Select function XX

- Display will appear as shown
- Press 0 and 8 buttons to select Function 08: "Read measuring value block"
- Press Q button to confirm input

Read measuring value block HELP
Input display group number XX

- Display will appear as shown
- Press 0 and 1 buttons to select "display group number"
- Press 0 button to confirm input

Read measuring value block 1 --->
1 2 3 4

- Display will appear as shown (1 to 4 = display zones)
- Only continue with check when engine coolant temperature is above 50°C (display zone 2)
- Press C button
- Press 0 and 2 buttons to select "display group number"
- Press Q button to confirm input

Read measuring value block 2 --->
1 2 3 4

- Display will appear as shown (1 to 4 = display zones)
- Read off figure shown in display zone 4
Specification: EGRn. active (EGR system not active)
- Increase engine speed
- Read off figure displayed in display zone 4
Specification: EGR active (EGR system active)
- Disconnect vacuum hose from EGR valve





- Connect US 8012 hand vacuum pump to valve -arrow- using piece of hose
- Operate hand vacuum pump
Idle quality must noticeably deteriorate

If NO

- Press (arrow) button
- Press 0 and 6 buttons to select Function 06 "End output"
- Press Q button to confirm input
- Switch OFF ignition
- Check pipes and connections for blockage, clean if necessary, replace EGR valve if necessary
- Check EVAP canister purge regulator valve activation
- Check DTC memory