3.4 Cal vs. Non Cal Air fuel sensor

A few weeks ago I had to replace upstream A/F sensor, got home with the new part and the connectors were different, turned out the part number is for CA emissions which the vehicle doesn't have. The wires are the same, so needing the vehicle I trimmed the tabs so the connector would fit. Now I am getting P1135 heater circuit. I guess I am wondering if the difference between the two would be causing the P1135. The engine seems to run fine.

 

What year truck? IIRC ‘01-‘04 were almost all CA spec, with a few exceptions.
I would guess that the ECU is expecting a different voltage for the heater circuit, so while the sensor might not be bad it probably is what is causing the DTC. Recommend getting the correct sensor and plug for your truck.

 

It is a 99 4runner limited

 

Might be a poor connection on the heater circuit