Operation CHARM: Car repair manuals for everyone.

Manufacturer Code Charts: 2628


[8] Mass air flow sensor: Plausibility


Possible cause:

- B2/6 (Left hot film mass air flow sensor)
- B2/7 (Right hot film mass air flow sensor)
Affected functions:

- Engine diagnosis

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Test 1: Inspect charge air system for leaks.

Test 2: Check component Hot film mass air flow sensor.

1. Inspect charge air system for leaks.
Inspect charge air system for leaks.
Important notes

- The following test sequence has changed.
- Follow the test procedure precisely!
- The test must be performed with the engine oil cap removed.
Communication with ECU required

2. Check component Hot film mass air flow sensor.

Test 2.1: Check component B2/6 (Left hot film mass air flow sensor).

Test 2.2: Check component B2/7 (Right hot film mass air flow sensor).

2.1. Check component B2/6 (Left hot film mass air flow sensor).
Check signal of component B2/6 (Left hot film mass air flow sensor) via actual value with engine OFF.
Test prerequisites

- Ignition ON
- Engine not running
- The air extractor system may not be connected to the exhaust system during the test.
- The hot film MAF sensor must have no air flow during the no-air test.
- Battery voltage is OK.
Status of associated actual value
- Engine speed:Warning! Communication with ECU required.


2.2. Check component B2/7 (Right hot film mass air flow sensor).
Check signal of component B2/7 (Right hot film mass air flow sensor) via actual value with engine OFF.
Test prerequisites

- Ignition ON
- Engine not running
- The air extractor system may not be connected to the exhaust system during the test.
- The hot film MAF sensor must have no air flow during the no-air test.
- Battery voltage is OK.
Status of associated actual value
- Engine speed:Warning! Communication with ECU required.