90 Quattro 20V L5-2309cc 2.3L DOHC (7A) (1990)
4.
Start engine, making sure all electrical loads are turned OFF. Radiator cooling fan must not be running during this test!
5.
Rev engine from idle to about 4,000 rpm and note voltage.
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Voltage should vary between approx. 1.5 and 3.4 volts as engine rpm varies. If not, replace air mass sensor.