I have an 04 plate Vectra-C 2.2 Direct Auto. Recently the Exhaust Gas Indicater warning light came on and stayed on. A small local garage undertook a code reading and found P0136 - O2 Sensor Bank 1 High Voltage and P0141 O2 Sensor Bank 1 Open Circuit. I had a new O2 Lamda sensor fitted but the light came back on the next day. Any ideas ? Thank you.