LMM Resistor Values: Understanding & Troubleshooting

hi everyone,

My TDI (G4, 81kW, AHF) has a faulty mass airflow sensor (MAF). Can anyone tell me the resistance values for this part at normal ambient temperature?

hello
Berni.

Hi.

Unlike, for example, a simple temperature sensor, the LMM (Laminar Mass Flow Meter) is an "active" electronic component. Therefore, no (meaningful) resistances can be measured from the outside, but only the output voltage, which varies depending on the airflow between approximately 1.5 (idle) and 4.58 (approximately full load) volts.

Hi

The LMM (Luchtmassenmesser) is - unlike, for example, a simple temperature sensor - an 'active' electronic component. Therefore, no (meaningful) resistances can be measured from the outside, but at most the output voltage, which varies depending on the airflow between approximately 1.5 (idle) and 4.58 (approximately full load) volts.

I was kind of thinking along those lines. Do you have any idea how I can find out if the mass airflow sensor (MAF) is actually defective or not?

hello
Berni.

Hi.

Quote:

Do you also have no idea how I can find out whether the LMM is actually defective or not?

Measuring the output voltage can provide clues: insert a measurement lead into the interior, connect a voltmeter, and perform a full-load acceleration up to 4000 rpm. The voltage should continuously increase until it reaches approximately 4.5 volts (if I remember previous posts correctly).

If the voltage is too low, try cleaning it with brake cleaner spray. If nothing helps, then replace it.