Signal Too Low

Signal too low

Checking components and wiring
Check the mass air flow (MAF) sensor connector. Check for contact resistance and oxidation.
Check for air leakage in the intake system and for damage to hoses etc.
Check the power supply cable between system relay terminal #5 and mass air flow (MAF) sensor terminal #2. Check for an open-circuit.
Check the signal cable between engine control module (ECM) terminal #A22 (#A22) and mass air flow (MAF) sensor terminal #5. Check for an open-circuit. Check for a short-circuit to ground.
Check the power supply cable between engine control module (ECM) terminal #A39 (#A39) and mass air flow (MAF) sensor terminal #4. Check for an open-circuit.

Hint: With the ignition on and the mass air flow (MAF) sensor connector connected the voltage at mass air flow (MAF) sensor terminal #2 must be approximately U bat.

Remedy as necessary.

Other information
- Connecting the breakout box, B5254T2 Connecting the Test Box
- Check for air leaks in the intake system Air Leaks in the Intake System, Checking
- For information about signals for 5 cylinder engines: Signal specification Signal Specification
- For information about signals for 6 cylinder engines: Signal specification Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals









Continue - Verification

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off
- Reinstall the connectors, components etc.
- Ignition on
- Check that the air flow is correct. The value must be approximately 0 kg/h with the engine switched off
- Start the engine. Read off the air flow. The value may vary by between 12-20 kg/h at idle speed, depending on the engine load and temperature. The value may be in excess of 20 kg/h if the engine is cold
- Increase the engine speed (RPM) and check that the air flow increases with increased engine speed.









Are the values correct?

Yes - Verification completed

No - Fault-tracing information

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Fault-tracing information




Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - Exit Fault-Tracing

No - Attempt New Test

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Attempt New Test - Checking components and wiring

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