Service Guys Clueless on error P0128

[CoryM]

Originally Posted by werther

First off thank you all for the suggestions/opinions. I appreciate it.

So I went back to the dealership/service center. We sat with the manager and the technician.

Basically they went step-wise changing parts that trigger P0128. As follows:
- Tstat
- Cooling system
- ECT sensor

Next in line...
The WIRE HARNESS

They walk me through those steps. Yes, CoryM that is what they are planning to do.

They showed me the factory white page of the wire and it is a hell of a job for such an error that a priori seems so innocent, I mean, it isn't that the car overheats or can't run!

Anyways... we reached a deal for parts cost only which I seemed fair.

This made me wonder of you guys driving your Yaris for over 100k miles... how much of this stuff you have to (or I will have to) go though only to keep this beautiful car.

Wiring harness issues are not common with this car, but can happen on any. Especially if the car has been in a crash or had work done where the harness may not have been correctly routed/secured. Just throwing it out there, but in that entire engine harness, there are only 2 wires that go to the sensor from the computer. In some cases, I have just replaced the required wires, and routed the new ones on the outside of the harness. It's not ideal, but is much more cost effective. No question that replacing the harness is better, but if the two wires are done correctly you will still correct the issue.

Cheers.