OBD 1.5 O2 Sensor Throws Code

[jeremy_gt]

My 1995 4.3 TBI threw a check engine light on me. I first tryed to check the code myself with my OBD1 GM code reader. The plugs were different. I took it to Auto Zone where they told me that it has a OBD2 jack, but that they can't read it because its OBD1.5. I then take it to Aamco tranmission where they read it and say the O2sensor is reporting that the engine is running lean. The tech says that my cat probbly needs to be replaced, or the sensor is bad. I tell him I have a test pipe. He says thats my problem. I have been running this test pipe for over a year no problem. I am going to replace the sensor and see if that does it, but does any one have any input. My truck only has one O2 sesnor and its before the cat. The computer should have no idea weather or not a cat is present.

[Maximus]

Having no cat will not throw a code on your truck.If you have a lean condition it could be the sensor but it could be a few other things to.Test the sensor and see if it is bad.

[T Man]

He told you it was the cat because he wanted to sell you a cat. Test the O2 sensor with a voltmeter and see what it is reading. If the sensor is bad it will be an easy fix, if you are actually running lean then you have an entirely different issue to deal with.