Checking the air flow meter (VW Lt 2d)

1. Connect the VAG 1551 tester and, by entering "01" "Engine electronics", select the engine control unit. The engine should be idling. The display should show the following information:

• Fast data exchange HELP
• Dial function XX

2. Press "08" to select the "Read Block of Measured Values" function and confirm with the "Q" button. The display should show the following information:

• Reading the measured value block HELP
• Enter group number XXX

3. Press "0" and "10" to select the "Display Group 10" function and press "Q". Accelerate the vehicle in 2nd gear, starting at 1500 rpm, with the accelerator pedal fully depressed. Press PRINT on the VAG 1551 tester at 3000 rpm. The accelerator pedal should be fully depressed at this time. The display should show the following information:

Reading measured value block 10 → 1320 mg/stroke 1027 bar 2150 bar 100%

(The original article is available on the website: VWMANUAL)

The set value is displayed in field 4 of the display (accelerator pedal position).

4. If the specified value is not achieved, repeat the test and accelerate the vehicle with the accelerator pedal fully depressed. The display should show the following information:

Reading measured value block 10 → 1320 mg/stroke 1027 bar 2150 bar 100%

The set value is shown in field 1 of the display: over 1300 mg/stroke (intake air).

5. If the specified value is not achieved, replace the flow meter.

6. If field 1 of the display constantly shows a value of approximately 514 mg/stroke, press "→".

7. Press "06" to select the "Quick Data Exchange" function and confirm by pressing the "Q" button.



8. Turn off the ignition.

9. Disconnect the connector from the flow meter. Turn on the ignition.

10. Measure the voltage between the terminals of the air flow meter connector (figure 4A.18).

Connector contacts	Specified value
2 + "mass"	Approximate battery voltage
2 + 3
4 + "mass"	About 5 V
4 + 3