With Manufacturer's Scan Tool

Secondary air system, 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

Note: All functions which could previously be performed V.A.G. 1551/1552 can also be performed with the new tester VAS 5051.





Test conditions
^ Fuses must be OK.





^ Main fuses must be OK.
^ Battery voltage must be at least 11.5 V
^ All electrical consumers, e g. lights and rear window defroster must be switched off.
^ If the vehicle is equipped with air conditioning, this must be switched off.
^ Fuel pump (FP) relay -J17- must be OK, checking:
Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations
^ No DTC's may be stored in DTC memory
Refer to Powertrain Management

Checking activation
- Check activation of Secondary air injection solenoid valve -N112- and Secondary air injection pump relay -J299- via On Board Diagnostic (OBD):
Refer to Powertrain Management

If activation is OK:
- Perform functional check.

Functional check
Test conditions
^ Vacuum lines and hose connections free of leaks.
^ Vacuum lines not blocked or kinked.
^ Selector lever must be in position "P" or "N" on models with an automatic transmission.
^ Coolant temperature must be at least 85°C.
^ When the temperature is reached, the operating cond Display group 1, display zone 2.
^ Oxygen sensor aging before catalytic converter OK, checking

Note: The diagnosis will only be ended if the oxygen sensor aging diagnosis before catalytic converter is completed successfully first.

Test sequence
- Test drive vehicle.

Observe the valid safety precautions when road testing, Refer to Air Injection,Service Precautions,
During the road test the following operating conditions must be fulfilled:
^ The coolant temperature must exceed 85°C.
^ When the temperature is reached, the operating conditions
Idling
Part throttle
Enrichment
Wide open throttle
Overrun
must be attained several times.
- Then:
^ Continue running engine at idling speed.
- Connect V.A.G 1551 Scan Tool (or V.A.G 1552). Start engine and select "Address word" 01 of engine control module:
Refer to Powertrain Management





Indicated on display:
- Press keys 0 and 4 for function "Initiate basic setting" and confirm entry with Q key.





Indicated on display:
- Press keys 0, 0 and 1 for"Display group number 1" and confirm entry with Q key.





Indicated on display: (1 . . .4 = display zones)
Only continue with the test when:
^ Coolant temperature is above 85°C -Display zone 2
- Change to display group 77 as follows:
- Press C key.





Indicated on display
- Press keys 0, 7 and 7 for "Display group number 77" and confirm entry with Q key.

Note: The engine must not be loaded during this diagnosis, if this occurs the diagnosis will be aborted and will not start again until the engine is revved-up.





Indicated on display: (1 . . .4 = display zones)
If the diagnosis is initiated by the engine control module the display in display zone 4 jumps from "Test OFF" to "Test ON".

Note: This process can take approximately 40 seconds.

- Leave engine running at idling speed until display zone 4 displays specification"Syst. OK."..
If "Syst. OK" appears in display zone 4:
- Press (arrow) key.
- Press keys 0 and 6 for function "End output" and confirm entry with Q key.
- Switch ignition off.
If "Syst.n.OK." appears in display zone 4:
- Press (arrow) key.
- Check DTC memory:
Refer to Powertrain Management
- Read readiness code
- Generate readiness code again if DTC memory has been erased or engine control module disconnected from permanent positive supply
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 combi-valve.