hi guys got a d40 with no cat and dpf delete was smoking white lots so put dpf back on and after limited driving the dpf light came on and now i think its in limp mode . we put the dpf delete pipe back on and nothing changed. i think the oxygen sensor on dpf suspect as runs exact the same with it or not. i think the resistance of the heater wires is meant to be between 10 and 20 ohms mine is 2 i tried another that is 9 ohms and no change will be buying auggies sensors but how to properly test the 4 wire oxygen sensors and will it get it out of limp mode . the only code it threw was 2002 which is dpf