Looking at a 4runner with check engine light tommorow. Familiar with these codes?

[Jo2]

It's showing:

P0115 Engine Coolant Temperature Circuit Malfunction
P0116 Engine Coolant Temperature Circuit Range/Performance Problem

P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)

Google says this is a bad ect sensor or pcm. Are those pricey fixes?

 

[4yotaguy]

Liek you, I am new here, but I think more information is needed aside from the codes. Fault codes can indicate other issues and from what I have read here (read the sticky's) a sensor is no biggie, but coolant issues on the mechanical side can be a real issue.

The year, mileage, overall coolant system condition would be helpful. A faulty O2 sensor is no biggie.

 

[Doc2012]

The O2 sensor could cause all those codes. If you get it, replace with a DENSO sensor.

 

[TheDurk]

The O2 sensor could cause all those codes. If you get it, replace with a DENSO sensor.

I would post the same thing if it was Sensor 1. But the fact that it is Sensor 2 has me scratching my head.

I know a bad front sensor can fool the ECU into thinking both the rear sensor and the ECT are bad. Ideally, I would get a live scanner that can read the engine temp output and see if those look reasonable. If they do, change both sensors if they are due (80k+). Or, do one and then the other. My gut tells me it's not just the rear sensor. It might even be a wiring problem.

It would be really nice to see the output from all three sensors. Then I think we could make the call what to do first with some authority.

 

[MAZZUMA]

I know this thread is pretty old but its for anyone trying to fix a P0115 code, I was able to replace my Coolant Temp Sensor which fixed all high idling issues as well as the code.