P0125

[zappy]

I have 2002 SC430 with 90K mile.

I brought it to one Autozone and they said it's coolant problem.

-> added coolant

I brought it to a Lexus dealer and they said b1s1 oxygen sensor needs to be replaced.

-> didn't believe

I brought it to a Meineke and they said thermostat needs to be replaced.

-> did, but the engine check sign came back on after 5 min driving.

I bought a OBD II reader and found the error code is P0125, and erased it. But it came back on after 5 min driving.

I bought b1s1 O2 sensor (BOSCH 13441) and had a local repair shop replace it.

-> drove 120 miles and deleted VSC & VSC off signs by zero calibration, but the engine check sign came back on

I brought it to an Advanced Auto Parts and they said the error code is P0125 and deleted it.

-> It came back on after 5 min driving.

I checked the temperature gauge before and after driving, but it seems normal.

Now what should I do?

[emg2919]

It is a bad 02 sensor I bet. I have the same error, and before I had a p0135. I changed the 02 sensor, but the shop (Toyota) that did it, I believe pulled one of the wires out too far and now the new o2 sensor is not connected fully. I bet if you change your o2 sensor this will be fixed.

I am bringing my 2002 sc430 to the lexus dealership to change my o2 sensor and fix this connection issue soon. All signs of yours point to bad o2 sensor or bad o2 sensor connection.