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
– 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)