With Manufacturer's Scan Tool
Idle Speed, Checking
NOTE:
Idle speed, ignition timing and CO content not adjustable.
The idle speed is regulated to specification by the throttle valve positioner in conjunction with the DIS function.
CO content regulated by oxygen sensor control. Malfunctions in oxygen sensor control are detected in On Board Diagnostic (OBD) and stored in DTC memory.
Special tools, test equipment and auxiliary items
- Scan tool VAG 1551 or vehicle system tester VAG 1552 with cable VAG 1551/3B
Checking conditions
- Exhaust system between catalyst and cylinder head must be free of leaks
- All electrical consumers, e.g. lights and rear window heating must be switched off
- If the vehicle is equipped With an air conditioner, this must be switched off
- On vehicles with automatic gearbox selector lever in "P" or "N" position
- Coolant temperature must be at least 85°C, see display group 04, display zone 3
- Intake air temperature less than 60°C, see display group 04, display zone 4
Test sequence
- Connect scan tool V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine must be running at idle speed. Connecting scan tool and selecting Engine Control Module (ECM). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAG 1551 Scan Tool, Testing and Inspection
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Checking and erasing DTC memory. Refer to "Displaying, Reading and Erasing Trouble Codes/With Manufacturers Scan Tool/DTC Memory, Checking And Erasing", Testing and Inspection
- Read-out the readiness code. If the DTC memory has been erased or the engine control module was disconnected from permanent positive, the readiness code must be generated again.
Refer to "Displaying, Reading and Erasing Trouble Codes/DTC Memory, Checking And Erasing", Testing and Inspection
Refer to "Displaying, Reading and Erasing Trouble Codes/Generating Readiness Code", Testing and Inspection
- Leave scan tool V.A.G 1551 connected.
- Continue running engine at idle speed.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press keys 0 and 4 for the function "Basic Setting" and confirm entry with Q key.
Indicated on display
Basic setting
Input display group number XXX
- Press keys 0, 0 and 1 for "Display group number 1" and confirm entry with Q key.
Indicated on display (1-4 = Display zones)
System in basic setting 1 ->
1 2 3 4
NOTE: In the "System in basic setting" function the EVAP canister purge regulator valve -N80- is closed and the air conditioner compressor switched off.
- Check the adjustment conditions for basic setting in display zone 4.
Display Group 1:
Significance of 8 digit number block
If the specification is obtained:
- Briefly increase engine speed (rev-up) and then allow engine to run at idle speed for 2 minutes.
Checking idle speed
- Change to display group 56 as follows:
- Press C key.
- Press keys 0, 5 and 6 for "Display group number 56" and confirm entry with Q key.
Indicated on display (1-4 = Display zones)
System in basic setting 56 ->
1 2 3 4
- Check the actual idle speed in display zone 1.
- Check the specified idle speed in display zone 2.
- Check operating mode in display zone 4.
Display Group 56:
Significance of 5 digit number block
If the specification is obtained:
- Press -> key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off ignition.
Continuation
If the idle speed is not obtained:
- Adapt ECM to throttle valve control module.
- Carry out test drive.
Observe the valid safety precautions when carrying out a road test.
- Again check the control module DTC memory.
- Repeat the idle check.
If the specifications are not obtained again:
- Check throttle valve control module. Testing and Inspection
- Check intake air system for unmetered air. Testing and Inspection
- Check the operating condition of engine. Refer to "Scan Tool Testing/Measuring Value Blocks/Engine Operating Modes, Checking", Testing and Inspection
- Check the signals from/to air conditioner. Testing and Inspection