Checking engine operating mode — AUDI

Note:

Checks whether engine control unit recognises the engine operating modes idling, overrun, part throttle, enrichment, full throttle.

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

Fault reader V.A.G 1551 (or vehicle system tester V.A.G 1552) with cable V.A.G 1551/3

Test conditions

Coolant temperature must be at least 80 °C, =>display group 04, display zone 3.

Test sequence

Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine control unit => Page
01-7
.)

Rapid data transfer
HELP
Select function XXX
Indicated on display:

Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

Read measured value block
Input display group number XXX
Indicated on display:

Press keys 0, 0 and 5 for "Display group number 5" and confirm entry with Q key.

Read measured value block 5
⇒
1
2
3
4
Indicated on display:
(1...4 = Display zones)

Check whether the control unit recognises the operating mode (display zone 4):

Idling:

As long as the engine is running at idling speed idling must be displayed
Display: Idling

Overrun mode:

Increase engine speed to above 3000 rpm.
Close throttle abruptly.

As long as the engine speed is above 1400 rpm overrun must be displayed
Display: Overrun

Note:

Below 1400 rpm idling speed will be recognised.

Part throttle:

Rev up evenly.

As long as the engine is being revved up evenly, part throttle must be displayed
Display: Part throt.

Enrichment:

Floor accelerator pedal (onto throttle valve stop).

Acceleration enrichment must be displayed briefly
Display: Enrichment

Full throttle:

Floor accelerator pedal (onto throttle valve stop).

Full throttle must be displayed briefly
Display: Full throttle

Note:

A test drive may have to be performed to show "Full throttle" in display.

Observe the valid safety precautions when carrying out a road test => Page
24-24
.

Press ⇒key.
Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the specifications are not attained:

Interrogate fault memory, if necessary, repair any faults and then erase fault memory => Page
01-16
, interrogating and erasing fault memory.
Check throttle valve control part
=> Page
24-34
.
Check parts of the electronic throttle control (EPC) for ease of movement:

=> Repair group 20; Electronic throttle control (EPC); Servicing parts of the electronic throttle control (EPC)
Motronic injection and ignition system (4-cyl.)
Electronic throttle control (EPC)
Servicing parts of the electronic throttle control (EPC)