Car: 2001 GS 300

Issue: P0125 Insufficient Coolant Temperature

What I replaced so far:
Radiator (Megan Radiator)
Radiator Fans (Aftermarket)
Thermostat (Dealer)
Radiator sensor (Dealer)
Coolant sensor in on the block of engine (Dealer)

I don’t know why it shows this code, I replaced almost everything that is coolant related but it still shows up. Any suggestions?

 

It's not just about the cooling system. This is an extensive error code that includes many parameters of the fuel injection system.

 

I accidentally broke the signal wire on B2S1 on my 01 GS and ended up with this code. Having a way to monitor live data will be very important to help diagnose the issue.

 

What is interesting about this situation is that the dealership did nothing to troubleshoot this diagnostic code, but limited itself to working only with the cooling system.

 

Get a way to read your ECU's accessible outputs such as coolant temp with something like the Torque app and a compatible bluetooth OBD2 plug. Then you'll be better informed about what's going on and this should help you troubleshoot things better.

 

This can be caused by a bad O2 sensor or wires. This happened to me. The harness had a broken O2 sense wire.

Use a DMM to check O2 voltage on the upstream sensors. Best location is at the ECM.

 

Thank you everyone for the suggestion, the problem was with the bank 2 sensor 2 O2 sensor, the power to the O2 wire was snapped off from old owner, I just had to weld it back and it is good.