P1101 Subaru HO2S11 Sensor Circuit Voltage Too Low Air Leak

Possible causes

– Faulty Mass Air Flow Sensor
– Air leak before or after sensor
– Mass Air Flow Sensor harness is open or shorted
– Mass Air Flow Sensor circuit poor electrical connection

What about the obd code?

The Engine Control Module (ECM) detected a Mass Air Flow (MAF) sensor signal above or below calibrated limit

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1101 Subaru Description

The Mass Air Flow (MAF sensor circuit is monitored by the Powertrain Control Module (PCM) for an out of range air flow (or voltage) input. If during key ON engine OFF the air flow voltage signal is greater than 0.27 volts the test fails. Likewise, if during key ON engine running, an air flow voltage signal is not within 0.46 volt to 2.44 volts, the test fails.