Possible causes
– Faulty O2 Sensor
– O2 Sensor harness is open or shorted
– O2 Sensor circuit poor electrical connection
– O2 Sensor harness is open or shorted
– O2 Sensor circuit poor electrical connection
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P1133 VOLKSWAGEN OBD Code Description
A Heated Exhaust Oxygen (HO2S) sensor indicating rich at the end of a test is trying to correct for an over-lean condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.