Hey fellow gsf owner. I have a problem with my gsf having the code p2238 p2239 and p2253. I have replace both upstream o2 sensor and the code is still there. Anyone have this issue. My car is full bolt on and tuned. And it seems like the car fuel system is in open loop and won’t come out of it. Could it be another sensor causing it to malfunction. Car still runs and drive just burning alot of fuel and have rough idle

 

Are you running O2 harness extenders? Those three codes are all for the same sensor (driver's side wideband O2 in the header collector). The first two are kind of not so important. The third one is critical - it says the ground for the sensor is not good. If you have extensions on this, then they're likely not doing well. My IS F got really pissed off when one of my extenders started acting up. Rerouting it helped, but I am not entirely convinced extensions are made of the same quality connectors Lexus uses.

TIS says:This diagnosis is the same for all three codes which makes me suspect the connection is not good, or the sensor got dropped before install and is damaged.

 

I just replace new extension harness for the o2 and check all connector and everything and it still pop up the same code. Ecu still read 3.3 volts when the car is off but then when it’s ok it around 1.5volts but when accelerating it drops down. But my fuel system is saying open loop.

 

Open loop is based on coolant temperature. Are you sure your coolant sensor is working correctly?

 

I haven’t tested the coolant temperature sensor but the temperature seem to be in the middle like it’s always been. Could it still be faulty even if it’s not over heating ?

 

The indication on the gauge cluster could be fine, but something may not be right with the ECM. The best way to check this is with a scan tool or Techstream so you can see what is getting reported to engine management.

 

I think my best option is to just take it to a Lexus specialist shop and let them look at it. Thank you. Btw.

 

Good luck with that. If you're local to north Atlanta, I can plug in Techstream and take a look for you. LMK.

 

That would be great. Where are you located. I can swing by Monday or whenever you’re free and get you to see what could be the problem. Thanks in advance man.