Operation CHARM: Car repair manuals for everyone.

Idle Speed: Testing and Inspection

Idle speed, checking

NOTE: Idle speed, ignition timing and CO-content are NOT adjustable.

Requirements
- engine coolant temperature 8O°C (176°F) minimum
- all electrical consumers switched OFF
- A/C switched OFF
- exhaust system must be leak tight

- start engine and let idle
- activate DTC MEMORY (Fault memory) and then erase
- connect EPA 105 CO tester to CO tap tube using VAG 1363/3 adaptor

After connecting the VAG 1551 Scan Tool, the display will alternate between the two following operating modes:





- press 1 button to select operating mode "Rapid Data Transfer"
- display will appear as shown





- press 0 and 1 buttons to select address word "Engine Electronics"
- display will appear as shown





- press Q button to enter input
- press => button
- display will appear as shown





- press buttons 0 and 4 to select function 04 "basic setting"
- display will appear as shown





- press Q button to enter input
- display will appear as shown





- press 0 and 1 buttons to select display group 01
- display will appear as shown





- press Q button to enter input
- display fields 1 through 4 will appear as shown





NOTE: When this mode is selected; the EVAP solenoid valve I (N 80) is closed.

- observe display field 2
- when the temperature exceeds 80°C (176°F) continue to next step

- raise engine speed briefly then let engine idle for 2 minutes
- read display value for engine RPM and ignition timing point as follows
- display field 1 = engine RPM
must be 650 to 750 RPM's
- display field 4 = ignition timing point
must be 6° BTDC and fluctuating

- observe CO content on tester
- checking value must be 0.3 to 1.5 Vol.%

- press => button
- press 0 and 6 buttons to select function 06 "Ending output"
- display will appear as shown





- press Q button to enter input





If specified RPM value not obtained
- check gas pedal for ease of movement, correct as necessary
- check dashpot, Adjustments
- check TP (throttle Position Sensor), Testing and Inspection
- check IAC valve (Idle Air Control), Testing and Inspection
- check EGR valve, Testing and Inspection

If all specified values are obtained
- check intake system for air and vacuum leaks