Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ VAS 5051 with VAS 5051/1

or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Test requirements:

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

Notes:

• ◆ The idling speed cannot be adjusted.
• ◆ The idling speed is tested during the basic setting of the engine.
• ◆ During basic setting, the solenoid valve for the active carbon canister (valve -N80) is closed and the air conditioner compressor is switched off.

Test sequence

• ‒ Interrogate fault memory . The fault memory must be clear. If necessary, rectify any faults and erase the fault memory. Switch off the engine, then start up again. Take vehicle for a test drive and interrogate the fault memory again to make sure it is clear.
• ‒ Leave engine idling.

• ‒ Enter "04" to select "Start basic setting" and confirm with Q key.

• ‒ Enter "056" for "display group number 056" and confirm entry with Q key.

• ‒ Check whether the engine speed in the display zone 1 (actual speed) is within the permitted tolerance range.

Notes:

• ◆ The engine speed in display zone 1 (actual speed) is the actual engine speed.
• ◆ The engine speed in display zone 2 (specified speed) is a theoretical value calculated by the engine control unit.
• ◆ During idling, the engine control unit always tries to adapt the actual engine speed to the specified engine speed.
• ◆ This means that during idling the actual engine speed must always approximate to the specified engine speed.
• ◆ Display zones three and four are there for information but are irrelevant to the control of the engine idling speed.

If specified value is attained:

• ‒ Press the ⇒key.

If specified value is not attained:

• ‒ Interrogate fault memory again .
• ‒ If fault memory is erased the readiness code must be produced again => Page 01-69.

If the idling speed is too high or too low and there are no faults recorded in the fault memory, carry out the following tests marked with a dot:

• ● Check induction system for unmetered air => Page 24-70.
• ● Check throttle valve control unit .
• ● Check solenoid valve for active carbon canister continuously open, check .
• ● Perform adaption of throttle valve control unit .

Significance of 5-digit readout of display group 056