Scaner Code 41, 89 Ranger

[Brian1]

I hooked up my scanner to an 89 Ranger with the 2.9L v6 and I am getting a code 41: no exhaust gas oxygen switching detected - always indicating lean.

This is throwing a CEL. It has a new O2 sensor within the last 4 months or so and the exhaust pipe shows it is more on the rich side than lean. Anyone know what this could be?

 

[chbtech]

The code certainly indicates an O2 sensor problem, so you might want to re-check the wiring and connector at the O2 sensor. The wiring could be broken, burnt or bare and the connector could be burnt or corroded. If you want to check the voltages of the wires (assuming there are 3 ), with the ignition in 'run', one wire should be ground, another should be 12V I think and the other should be 5V or less but not zero. The 5V one should fluctuate when the engine is running and the exhaust is hot. There are numerous posts on testing O2 sensor circuits, so a search may be helpful.