Simple job or so I thought. Code p1135 and p1155 A/f sensor heat circuit fault B1 S1 and B2 S1. I took this as being after Cat sensors. Checked resistance and both at 13 ohms and drawing 1.2 amps and going down quickly after 15 sec of engine running to .7amp. Checked the sensors before cat and no resistance or amp draw!! on both sensors. Replaced the faulty top sensors but as I thought still the same codes. Fitted one new sensor to after cat but still same codes come back after 20 sec or so. They were not Toyota sensors but before I go down the road and expense of fitting am I missing something? I am getting 12 volts and an earth on the heat circuits of all sensors. Hope someone can help.
Regards
Les