P0128

[Amos7514]

Hey how’s it going I’m getting a p0128 on my 04 expy 5.4 with 90k what should I check and is it okay to drive?

 

[ManUpOrShutUp]

Check the tstat. Even if it's fine, it's a good idea to replace it while you're there anyway.

 

[Amos7514]

I replaced the Tstat it was fine for 3 weeks then it came back on should I replace the sensor?

 

[Hamfisted]

Do you have a live data capable OBDII reader or ForScan ? See what the sensor is reporting on live data. Do you have a infra red temperature gun ? See what temp the thermostat housing area is actually at with the gun. What brand of thermostat did you install ?