check engine AUDI A4 1997 B5 / 1.G AFC Engine Idle Speed Checking Workshop Manual

24-16


Idle speed, checking

Notes:

Idle speed can NOT be manually adjusted.
Idle speed is checked during "Basic Setting"
function 04. After selecting function 04, the
learning values for idle speed and oxygen
sensor control are relearned (idle speed and
CO content are adjusted independently)
page 01
-150
.

CO content is controlled by oxygen sensor
control for a specified value. Interference within
oxygen sensor control will be captured via the
On Board Diagnostic system and stored in DTC
memory.

Checking requirements:
Engine coolant temperature: 85 C (185 F)
minimum

All electrical consumers must be switched off
(A/C, rear window defroster, etc.)
Transmission range selector lever in "P" or
"N" position
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Throttle valve must be at closed throttle
position (adjust accelerator pedal cable, if
necessary)

Repair Manual, 2.8 Liter V6 2V Engine
Mechanical, Engine Code(s): AFC, Repair Group 20


Exhaust system must be sealed leak-tight
No pressure measuring devices connected
to the system
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24-17

- Check DTC memory page 01
-13
.

No DTCs should be stored. If necessary:

- Repair malfunction.

- Erase DTC memory.

- Stop off engine and restart.

- Test drive and, as a check, check DTC
memory again.

Note:
Erasing DTC memory resets the readiness code
(as well as with address word 01, "Basic Setting"
function 04 and address word 33, mode 4).

- After checking DTC memory, start engine and
let idle.

CAUTION!

Do NOT run tests or record displays while the
radiator coolant fan is running.

-
Using VAG 1551 scan tool, select "Basic
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24-18

Basic Settin
g 3
1 2 3 4

Indicated on display
(1 to 4 = Display fields)
Notes:
If the specified value is not obtained:
Continue with test, if the engine coolant temperature exceeds 85 C
(185 F) display group 001, display field 1. In "Basic Setting" function 04 the EVAP canister purge regulator valve
-N80- is closed page 01
-150
.
- Briefly increase engine speed (RPM) and then let idle for another 2
minutes.
- Observe value in display field 1.
Specified value: 650 to 750 RPM
-
Push button.- Press buttons -0- and -6- to select "End Output" function 06.
- Press -Q- button to confirm input.
- Check DTC memory again page 01
-13
.
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