Checking idling speed and CO content — AUDI
Checking idling speed and CO content on Audi: factory workshop procedure for engines AAH, ABB, ADP, ADR. Full factory text, tools and checks.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 15 workshop diagrams for AAH
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
AEB
Test requirements:
No leaks in exhaust system
Coolant temperature at least 80 oC.
Throttle valve in idling position (adjust accelerator cable)
=> 4-cylinder Engine, Mechanics; Repair group 20; Removing and installing parts of fuel supply system; Servicing accelerator mechanism
4-cylinder Engine, Mechanics
Removing and installing parts of fuel supply system
Servicing accelerator mechanism
All electrical loads off.
Air conditioning switched off.
Pressure gauge not connected
Vehicles with automatic gearbox: Selector lever in position P or N
Checking idling speed
Notes:
The idling speed cannot be adjusted.
The idling speed is checked in function 08 "Read measured value block".
Interrogate fault memory =>Page
01-8
. 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.
Switch off air conditioner.
Switch off rear window heating.
Place selector lever in P or N position (automatic gearboxes).
Important!
The electric radiator fan must not be running.
Read measured value block (function 08) and select Display group 05 =>Page
01-49.
Read measured value block (5)
⇒ (1) (2) (3) (4)
Display:
Read off idling speed from Display zone 1.
Specification: 820...900 rpm
Press the ⇒key
Enter 06 for `End output' and confirm entry with Q-key.
If the specified result is not achieved, interrogate the fault memory again =>Page
01-8.
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:
Test idling switch =>Page
24-62.
Large quantity of unmetered air =>Basic setting of engine, Display group 01, 05 or 08.
Check throttle valve control part =>Page
24-58.
Testing CO content:
It is not possible to adjust the CO content.
It is not possible to test the CO content upstream of the CAT.
To assess the exhaust upstream of the CAT, it is necessary to check the Lambda control values and the Lambda learned values in the self-diagnosis.
Interrogate fault memory =>Page
01-8
. 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.
Read measured value block (function 08) and select Display group 03 =>Page
01-49.
Read measured value block (3)
⇒ (1) (2) (3) (4)
Display:
Do not proceed with the test until the coolant temperature shown in Display zone 3 has reached at least 80 oC.
Press the C key
Press keys 0 and 9 (Display group 09 is selected with 09) and confirm the entry with the Q key.
Read measured value block (9)
⇒ (1) (2) (3) (4)
Display:
Compare the displayed values to the specified values=>Page
01-86.
If the values are not as specified, rectify the fault and repeat the test.
Press the C key
Press keys 0 and 8 (Display group 8 is selected with 08) and confirm entry with the Q key.
Read measured value block (8)
⇒ (1) (2) (3) (4)
Display:
Compare the displayed values to the specified values =>Page
01-83.
If the values are not as specified, rectify the fault and repeat the test.
Press the ⇒key
Press keys 0 and 6 for "End data transfer" and confirm entry with the key Q.
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
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The story behind TorqFix → · How these pages are made →Workshop data on this page last updated 20 Sep 2026.