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
- VAG 1551 scan tool or VAG 1552 mobile scan tool with VAG 1551/3B cable
Test conditions
- Exhaust system between Three Way Catalytic Converter (TWC) and cylinder head must be free of leaks
- All electrical accessories, e.g. lights and rear window defroster must be switched off
- If the vehicle is equipped with air conditioning, it must be turned off
- On vehicles with automatic transmission selector lever in "P" or "N" position
- Engine Coolant Temperature (ECT) must be at least 80 °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 VAG 1551 scan tool ((VAG 1552). Start engine and select "Address word" 01 of Motronic Engine Control Module (ECM) -J220-. Engine must be running at idle speed. Connecting scan tool and selecting Motronic Engine Control Module (ECM) -J220-. [1][2][3]Connecting VAG 1551 Scan Tool
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
- Leave VAG 1551 scan tool connected.
- Continue running engine at idle speed.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -4- for function "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
- Check adjustment conditions for basic setting in display zone 4.
Specification: 1x111111
Significance of the numbers
NOTE: In the "System in basic setting" function the EVAP canister purge regulator valve -N80- is closed and the air conditioner compressor switched off.
Significance of 8 digit number block
If the specification is obtained:
- Briefly increase engine speed (RPM) (rev-up) and then allow engine to run at idle speed for 2 minutes.
Checking idle speed
- Continue running engine at idle speed.
- Change to display group 56 as follows:
- Press -C- button.
NOTE:
- Idling speed cannot be adjusted.
- Idling speed is tested during the basic setting of the engine.
- In the "System in basic setting" function the EVAP canister purge regulator valve -N80- is closed and the air conditioner compressor switched off.
WARNING!
The electric coolant fan must not be running.
- 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 mode in display zone 4.
Specification: 0x000 (Significance)
- Check specified idle speed in display zone 2.
Specification:
Manual transmission 760 RPM
Automatic transmission 700 RPM
- Check actual idle speed in display zone 1.
Specification:
Manual transmission 760 to 810 RPM 1)
Automatic transmission 700 to 750 RPM 1)
1) Engine idling at normal operating temperature
NOTE: During idling check the EVAP canister purge regulator valve and the air conditioner are switched off and the oxygen sensor control learning procedure is initiated.
NOTE:
- The value shown in display zone 1 is the actual engine speed.
- The value shown in display zone 2 (specified engine speed) is a theoretical value calculated by the Motronic Engine Control Module (ECM) -J220-.
- When the engine is idling the Motronic Engine Control Module (ECM) -J220- tries constantly to adjust the actual engine speed so that it adapts the specified value.
- This means that the actual engine speed when idling should be approximately the same as the specified engine speed.
Significance of 5 digit number block
If the specification is obtained:
- Press -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Switch off ignition.
Continuation
If the idle speed is not obtained:
- Adapt ECM to Throttle Valve Control Module -J338-. ECM, Adapting to Throttle Valve Control Module
- Road test vehicle.
Observe the valid safety precautions when road testing.
- Again check control module DTC memory.
- Repeat idle check.
If the specifications are not obtained again:
- Check Throttle Valve Control Module -J338-. Throttle Valve Control Module, Checking
- Check operating condition of engine.
- Check intake air system for unmetered air. Intake Air System, Checking For Leaks (False/Unmetered Air)
- Check signals from/to air conditioner. Air Conditioning (A/C) System Signal, Checking