Hello. We just picked up this es300 in very good condition. We took a trip and during that trip, the overdrive stopped working. We made it home in limp mode, I disconnected the battery, reconnected, and the car has been driving fine for a few days now. Checked at O'Reilly's and there is no code for the knock sensors, which is apparently often the problem when the car won't shift into 4th gear. But, the no-overdrive problem seems to occur at times when the coolant sensor, engine sensor, thermostat, etc., isn't performing/reading correctly. So, I figured I should address the codes I'm getting now and see if the no-overdrive problem returns (yes, someone removed the check engine light so these didn't pop up when we bought it):
P0125 - Insufficient Coolant Temperature for Closed Loop Fuel Control. After extensive reading, it seems that this code hardly ever occurs by itself and often resolves itself when you resolve another issue. So, I think we should wait on this and address the others first.
P1130 - Air/Fuel Ratio Sensor Circuit Range/Performance Malfunction Bank 1 Sensor 1. B1S1, I believe, is behind the engine near the firewall. After reading a lot online, I think that if the B2S1 is replaced, this code might go away
P1153 - Air/Fuel Ratio Sensor Circuit Response Malfunction Bank 2 Sensor 1. This is the sensor right up front. I'm thinking that changing this might fix the other codes as well. Or, this is the best place to start, I'm guessing.
P1155 - Air/Fuel Ratio Sensor Heater Circuit Malfunction Bank 2 Sensor 1. Again B2S1, the one in the front of the car that's easy to get to.
So, I guess I could buzz it over to my dad's house for him to check electrical continuity; or to figure out if the sensor's heater is working properly. However, I'm thinking simply replacing the sensor might be the best bet.
If I do change this sensor (B2S1), what is the Toyota part number? And, I've heard to not use off-brand parts for knock sensors, but since this is not a knock sensor, can I buy something locally at AutoZone that's readily available and comes with a warranty?
I'll probably do as you guys recommend. Much appreciated!!