With Manufacturer's Scan Tool
Idle Speed, Checking
NOTES:
- Idle speed, ignition timing and CO content are not adjustable.
- The idle speed is regulated to specified value by the throttle position sensor in conjunction with the DIS function.
- CO content regulated by Oxygen Sensor (O2S) control. Malfunctions in oxygen sensor control are detected in On Board Diagnostic (OBD) and stored as DTCs in DTC memory.
Special tools and equipment
- VAG1551 Scan Tool (ST) or VAG1552 mobile scan tool with VAG1551/3 adapter cable
Test requirements
- Exhaust system between Three Way Catalytic Converter (TWC) and cylinder head must be free of leaks
- All electrical consumers (e.g. lights and window defroster) must be switched off
- A/C switched off
- Automatic transmission selector lever in "P" or "N" position
- Cruise control system functioning correctly (if installed).
- Accelerator pedal cable adjustment OK.
- Coolant temperature at least 85°C, See display group 04, display field 3.
- Intake air temperature less than 60°C See display group 04, display field 4.
Test sequence
- Connect VAG1551 (VAG1552) Scan Tool (ST). [1][2]Reading and Clearing Diagnostic Trouble Codes
- Switch ignition on and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (when doing this engine must be running at idle).
- Check DTC memory. If necessary, repair any malfunctions and erase DTC memory.
Reading Diagnostic Trouble Codes
Clearing Diagnostic Trouble Codes
- Display readiness code. If DTC memory has been erased or the Engine Control Module (ECM) was disconnected from permanent battery (B+) voltage, the readiness code must be generated again. Monitors, Trips, Drive Cycles and Readiness Codes
- Leave VAG1551 Scan Tool (ST) connected.
- Continue running engine at idle speed.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -4- to select "Basic Setting" function 04 and press -Q- button to confirm input.
Indicated on display
Basic setting
Input display group number XXX
- Press buttons -0-, -0- and -1- to input display group number 1(001) and press -Q- button to confirm input.
Indicated on display: (1-4 = display fields)
System in basic setting 1 ->
1 2 3 4
NOTE: In the "Basic Setting" function the Evaporative Emissions (EVAP) canister purge regulator valve -N80- is closed and the air conditioner compressor is switched off.
- Check adjustment conditions for basic setting in display field 4.
Explanation of 6 digit number block
If the specified value is obtained:
- Briefly increase engine speed (rev-up) and allow engine to run at idle speed for 2 minutes.
Checking idle speed
- Change to display group 056 as follows:
- Press -C- button.
- Press buttons -0-, -5- and -6- to input display group number 56 (056) and press -Q- button to confirm input.
Indicated on display: (1-4 = display fields)
System in basic setting 56 ->
1 2 3 4
- Check actual idle speed in display field 1.
- Check specified idle speed in display field 2.
Explanation of 4 digit number block
If the specified value is obtained:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -Q- button to confirm input.
- Switch ignition off.
Continuation
If the idle speed is not obtained:
- Carry out adaptation of Engine Control Module (ECM) to throttle valve control module. Engine Control Module (ECM), Adapting to Throttle Valve Control Module
- Carry out test drive.
Observe the safety precautions when carrying out a road test. Technician Safety Information
- Check DTC memory again.
- Repeat idling check.
If the specified values are not obtained again:
- Check throttle valve control module. Throttle Valve Control Module, Checking
- Check signals from/to A/C compressor. Air Conditioning System Signal, Checking
- Check engine operating mode. Engine Operating Conditions, Checking