With Manufacturer's Scan Tool
Idle Speed Check
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 to specification by Oxygen Sensor control. Malfunctions in Oxygen Sensor control are detected by On Board Diagnostic (OBD) and stored in DTC memory.
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551 Scan tool (or VAG 1552) with VAG 1551/3 adapter cable
NOTE: All functions which could previously be performed with VAG 1551/1552 can also be performed with the VAS 5051.
Test prerequisites
- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical accessories, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with air conditioning, this must be switched off.
- Selector lever must be in position "P" or "N" on vehicles with an automatic transmission.
- Exhaust system between Three Way Catalytic Converter (TWC) and cylinder head must be free of leaks.
- Engine Coolant Temperature (ECT) must be at least 85 degrees C, See display group 4, display zone 3.
- Intake air temperature less than 60 degrees C, See display group 04, display zone 4.
- Three Way Catalytic Converter (TWC) temperature must be at least 380 degrees C,See display group 34, display zone 2.
Test sequence
- Connect VAG 1551 Scan tool (or VAG 1552) and select engine electronics control module with the "Address word" 01. When doing this the engine must be running at idle speed: ((VAG 1551 and Motronic Engine Control Module (ECM) -J220-, connecting and selecting).
[1][2][3]Connecting VAG 1551 Scan Tool
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory
Reading Diagnostic Trouble Codes.
- Then:
- Connect scan tool.
- Continue running engine at idle.
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -4- for function "Initiate basic setting" and confirm entry with -Q- button.
Indicated on display:
Basic setting
Input display group number XXX
- Press buttons -0-, -0- and -1- for "Display group number 1" and confirm entry with -Q- button.
Indicated on display: (1 to 4 = display zones)
System in basic setting 1 ->
1 2 3 4
NOTE: In the function "System in basic setting" the Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80- is closed and the air conditioner compressor turned off.
- Check adjustment conditions for basic settings in display zone 4:
Specification: 11111111
Significance of figures in 8 digit number block.
Connecting VAG 5051 Scan Tool
- Briefly increase engine speed (rev-up) and then allow engine to run at idle for 2 minutes.
Checking idle speed
- Change to display group 56 as follows:
- Press -C- button.
- Press buttons -0-, -5- and -6- for "Display group number 56" and confirm entry with -Q- button.
Indicated on display: (1 to 4 = display zones)
System in basic setting 56 ->
1 2 3 4
- Check operating conditions in display zone 4:
Specification: xx000
Significance of figures in 5 digit number block.
Evaluating Measured Value Blocks
- Check specified idle speed in display zone 2.
Specification: 700 rpm
- Check actual idle speed in display zone 1.
Specification: 640 to 720 rpm
- Press the -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with the Q button.
- Switch off ignition.
If the idle speed is not obtained:
- Erase learned values and adapt Motronic Engine Control Module (ECM) -J220- again.
- Carry out road test.
Observe the valid safety precautions when carrying out a road test. Refer to "Fuel Delivery and Air Induction/Service Precautions".
[1][2]Technician Safety Information
- Check the control module DTC memory again.
- Repeat Engine idle speed check.
If the specifications are not obtained again:
- Check Throttle Valve Control Module -J338- Refer under "Powertrain Management/Computers and Control Systems/Electronic Throttle Control Module".
Testing and Inspection
- Check operating condition of engine.
Engine Operating Mode, Checking
- Check intake air system for leaks (unmetered air).
Testing and Inspection
- Check signals from / to air conditioning system.
Testing and Inspection