NEED RTH: P0125 Code won't go away

[BrettinSanAntonio]

I’m still getting a check engine light with a P0125 code. I understand this means insufficient coolant temp for closed loop operation. I’ve replaced both O2 sensors and the thermostat (thought it might be sticking open) with Toyota parts. What’s left? Could the problem be coming from the coolant temp sensor? My engine is running at 190 degrees with very little change after warm up. The warm up time doesn't seem excessive to me but I guess the ECU doesn't like it. I tested the O2 per the FSM and they look good so I’m at a loss. Any ideas would be appreciated.

 

[landtank]

did you check the output voltage of a heated O2 sensor?

 

[BrettinSanAntonio]

No, I did not. I checked the resistance. CDan set me up with both of them back in January so they SHOULD be OK. Do you know what the output voltage should be? Do I need to set them up on a scope and look at the wave?

did you check the output voltage of a heated O2 sensor?

 

[landtank]

you need to check that output voltage to confirm that the circuit on the truck is OK. You could have an open or short that isn't allowing the heater in the O2 sensor to work.