P1137 Buick HO2S Circuit Low Voltage During Power Enrichment Sensor 2

P1138 Buick HO2S Circuit High Voltage During Decel Fuel Cut-Off Sensor 2

Possible causes
– Vacuum leak on engine
– Faulty Failed Mass Air Flow (MAF)
– Faulty HO2S
– HO2S harness is open or shorted
– HO2S circuit poor electrical connection
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
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