Idle Speed, Checking

NOTES:
- Idle speed, ignition timing and CO content are not adjustable.
- Idle speed is regulated within specification by the Throttle Position sensor in conjunction with the idle Speed Control function.
- CO content is regulated by the Oxygen sensor control system. Malfunctions in this system are detected via the On Board Diagnostic system and stored in DTC memory.

Special tools, testers, measuring instruments and auxiliary items required:
- VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable

Checking conditions:
- Exhaust system between cylinder head and Three Way Catalyst must be free of leaks
- Engine Coolant Temperature must be 85 °C minimum,
See Display group 04, Display zone 3
- All electrical consumers, e.g. lights and rear window defroster must be switched OFF
- A/C switched OFF (if installed)
- Automatic Transmission Range selector in "P" or "N" position
- Throttle cable adjustment OK

Test sequence:
- Connect VAG 1551/1552 Scan Tool
- Start engine and let idle
- Press 0 and 1 buttons to select "Address word" 01
"Engine electronics"
- Check DTC memory, if necessary, repair malfunction and then erase DTC memory
- With VAG 1551 Scan Tool connected, let engine continue to idle

Display will appear as shown

Rapid data transfer HELP
Select function XX

- Press 0 and 4 buttons to select Function 04 "Basic setting"
- Press Q button to enter input

Display will appear as shown

Basic setting HELP
Input Display group number XXX

- Press 0, 0 and 1 buttons to select "Display group 1"
- Press Q button to enter input

Display will appear as shown (1 to 4 = Display zones)

System in Basic setting 1 ->
1 2 3 4

Do not continue with check until the adjustment conditions in Display zone 4 are fulfilled
- Specification: 111111
- Briefly increase engine speed,then allow engine to idle for 2 min.
- Check specifications in Display zones 1 to 4 on chart.






Significance of Display Group 1






Significance of figures in 6 digit number block in Display zone 4, Display group 1


If specification obtained
- Press C button.
- Press 0, 5 and 6 buttons to select "Display group 56"
- Press Q button to enter input

Display will appear as shown (1 to 4 = Display zones)

Basic setting 56 ->
1 2 3 4

- Check specifications, Display zones 1 to 4 on chart.






Significance of figures in 4 digit number block in Display zone 4, Display group 56






- Press -> button.
- Press 0 and 6 buttons to select Function 06: "End data output"
- Press Q button to enter input
- Perform a road test and repeat the check.

NOTE: If DTC memory has been erased or the Engine Control Module was disconnected from it's voltage supply, the Readiness Code must be created again.