Idle Speed (RPM), Checking

Idle Speed (RPM), Checking

Special tools and workshop equipment required:

- VAS 5051.
- VAS 5051/1 adapter.

Test requirements:

- No leaks in exhaust system.
- Coolant temperature at least 80 degree C.
- Electrical devices switched off (radiator fan must not run during the test).
- Air conditioning switched off.
- Pressure gauge not connected.
- Vehicles with automatic transmission: Selector lever in position P or N.

NOTE:
- The idle speed (RPM) cannot be adjusted.
- The idle speed (RPM) is tested during the basic setting of the engine.
- During basic setting, the Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80- is closed and the air conditioner compressor is switched off.

Test sequence

- Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 - Engine electronics" in selection. Engine must be running at idle. Connecting VAS 5051 Scan Tool
- Check DTC memory. There must not be any DTCs stored. If necessary, repair any DTCs and erase the DTC memory. After erasing DTC memory, generate readiness code. Readiness Code, Generating
- Leave engine idling.

CAUTION: The electric coolant fan should not be running.

Display on VAS 5051:







- Under -1- select diagnostic function "04 - Basic setting".

Display on VAS 5051:







- 1 - Enter display group.
- Enter "056" for "display group number 056" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS 5051:







- Activate basic setting by pressing -A- button.
- Check whether engine speed (RPM) in display zone -1- (actual speed) is within permitted tolerance range.

Display Group 056:

- Exit function "04 - Basic setting" by pressing <- button.

If specified value is not obtained:
- Check DTC memory again.
- If DTC memory has been erased, generate readiness code. Readiness Code, Generating

If the idle is too high or too low and there are no DTCs recorded in the DTC memory, perform the following tests:

- Check intake air system for unmetered air. [1][2]Checking Intake Air System For Leaks (Unmetered or False Air)
- Check Throttle Valve Control Module -J338-. Throttle Valve Control Module -J338-, Checking
- Check to see if Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80- is continuously held open. Testing and Inspection
- Perform adaptation of Throttle Valve Control Module -J338-.

Significance of 5 digit indication of display group 056

Display Field 4: