1996 V6 Camry O2 Sensor nightmare
 

Hopefully someone can shed some light on a solution on this lingering problem.

I have a 1996 V6 Camry with 149k on it. Earlier this year the "Check Engine Light" came on and with a handheld code reader this message was P0135 sensor.

Since I had 149K on it, I decided to change both 02 Sensor..(California car)

Unfortunately I used Bosch brand before reading a previous thread that stated that it is better to use the Toyota OEM brand especially for California cars.

The bottom line is after about 150 miles that Check Engine Light will return, I will reset it and it will go for another 150 miles and then it will reappear. Mileage with or without the check engine light remains about 24 - 26 mpg...

So I changed again the rear 02 Sensor under the car with the Toyota brand and it still has the check engine light after 150 miles. Frustrating!

So what am I missing here?

Please advise.

Thanks..

Bosch can have issues Denso is preferred if not using Toyota. For any after market sensor (not Toyota brand) suggest NOT using one referred to as universal.

Code refers to a problem with heater circuit of the 02 sensor, Bank 1, Sensor 1 which is the first sensor on the exhaust system on the rear cylinder.

If you have the old 02 sensors use an ohm meter to check resistance of the heater circuit. Should be 11-16 ohms.

Heater circuit wire colors of sensors. One wire is always black/orange (12V power). The other wire can be violet/red, blue/black or purple/black depending on sensor location.

The brown wire is for the sensor itself, the other sensor wire color can be black, white, or red/blue.

You can also check for voltage at the engine computer located behind glove box. Measure voltage at each heater wire color noted above and ground at harness plug at computer. Should be 9-14v.

The California car used the same sensor as Federal.

If you replaced the sensor under the car, this would be Bank 1, Sensor 2.