Ford P1129 OBD-II Trouble Code Definition: P1129 Downstream Oxygen Sensors Swapped from Bank to Bank P1129 Ford OBD-II Trouble CodeDescription: Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1129 OBD Code Description Downstream Oxygen Sensors Swapped from Bank to Bank is one of the definitions for the P1129; however your vehicle’s manufacturer may […]