Testing air mass meter (vehicles as of model year 1998) — AUDI

AKL
Note:

From model year 1998 onwards the intake air temperature sender (G42) is integrated in the air mass meter. The sender is therefore no longer fitted as a separate engine component.

Test conditions

Fuse for air mass meter OK.

=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations

Coolant temperature at least 80 °C.
All electrical consumers, e.g. lights and rear window heating, must be switched off.
If the vehicle is equipped with an air conditioner, this must be switched off.
On vehicles with automatic gearbox selector lever in "P" or "N" position.

Connect the fault reader V.A.G 1551 (V.A.G 1552). Start the engine and select the engine control unit with "Address word" 01.
(Connecting fault reader and selecting engine control unit => Page
01-4
.)

Rapid data transfer
HELP
Select function XX
Display readout:

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

Read measured value block
HELP
Enter display group number XXX
Display readout:

Press keys 0, 0 and 1 for "Display Group 1" and confirm entry by pressing Q.

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

Check whether the coolant temperature is above 80 °C in display zone 2.
Change to display group 2 as follows:
V.A.G 1551: Press key 3
V.A.G 1552: Press↑key

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

Display zone 2 shows the intake air mass (milligrams per stroke).

Specification: 76...164 mg/stroke

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

If the specifications are not attained or there is a fault in fault memory relating to the air mass meter:

Disconnect the 4-pin connector -1- from the air mass meter -2-.
Connect multimeter (voltage test range) between engine earth and contact 3 on the connector.
Start engine and run at idling speed.

Specification: 11...15 V

Switch off ignition.
If the power supply is OK, test the signal wire and the earth connection => Page
24-37
.

If no voltage is present:

Check wiring from contact 3 to fuel pump relay (J17) according to current flow diagram.

=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations

Testing signal and earth wiring for air mass meter

Connect test box V.A.G 1598/22 to wiring harness for control unit.

Check wiring between test box and 4 pin connector for open circuit using current flow diagram.
Contact 1+socket 13
Contact 2+socket 12
Wire resistance: max. 1.5 ω
Additionally check all wires for short to one another.
Specification: infinite resistance (the wires must not be connected to each other)

If no wiring fault is detected:

Replace the air mass meter (G70) and the intake air temperature sender (G42).