Idle Air Control, Checking
IDLE AIR CONTROL, CHECKING
Functional check
- Functional check See Output Diagnostic Test Mode (DTM), refer to "On-Board Diagnostic". Testing and Inspection
Special tools, testers and auxiliary items
- VAG 1551 Scan Tool (ST) with VAG 1551/3 adapter cable
Test sequence
- Start engine and run at idle speed.
- Connect VAG 1551 scan tool and select "Rapid data transfer"operating mode.
- Press buttons -0- and -1- to insert "Engine Electronics" address word 01. Carry out selection at idle, refer to "On-Board Diagnostic". Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.
- Press -Q- button to confirm input.
Indicated on display
Read measuring value block HELP
Input display group number XXX
- Press -0-, -0- and -1- to input display group number 001.
- Press -Q- button to confirm input.
Indicated on display (1, 2, 3 and 4 = Display fields)
Read measuring value block 1 ->
1 2 3 4
NOTE: If something different is indicated on the display:
See VAG 1551 scan tool operating instructions.
CAUTION!
Do not continue with the check until engine coolant temperature exceeds 80 °C (display field 2).
- Briefly increase engine speed (RPM) by pressing on accelerator pedal, then allow engine to run at idle speed for 2 minutes.
- Press -C- button.
- Press -0-, -0- and -5- to input display group number 005.
- Press -Q- button to confirm input.
Indicated on display (1, 2, 3 and 4 = Display fields)
Read measuring value block 5 ->
1 2 3 4
- Read and record duty cycle in display field 3.
- Disconnect harness connector -1- from engine coolant temperature sensor -2-.
- Duty cycle must increase, then drop again to original value.
NOTE: Test can only be repeated after the DTC memory has been erased.
- Reconnect engine coolant temperature sensor connector.
- Press -> button.
- Press buttons -0- and -2- to select "Check DTC Memory" function 02.
- Press -Q- button to confirm input.
- Press -> button until all malfunctions still stored have been displayed.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -5- to select "Erase DTC Memory" function 05.
- Press -Q- button to confirm input.
- Press -> button.
- Press buttons -0- and -6- to select 'End Output" function 06.
- Press -Q- button to confirm input.