Contour Enthusiasts Group Archives Forums General Troubleshooting Fed up--going to the garage

I have a 96 Contour 2.5 It keeps throwing a code P0156 which is the circuit for the downstream bank 2 sensor. I have replaced the sensor twice. All the other sensors have been replaced. Cleaned the upper intake and throttle body, not to mention the totally crudded egr valve passages, and checked the wiring going to the sensor. I cannot find anything wrong what so ever. You reset the computer and take off in it, the light will stay off till you turn it off and then restart it. After you restart it you go down the road a mile and it comes back on. When the light comes on the exhaust starts stinkin. So I know that if I drive it with the light on it will mess up my new oxygen sensors and tune-up from running rich. Im so fed up now I am debating on ramming it in the garage and leave it. Has anybody had this problem or could it just be the computer is bad and not throwing a code for it being bad. I have run out of ideas.

Blaze

Sounds like plugged precats to me.

I second that notion....


Ray

I thought that also. But the code isnt for what readings the sensor is giving, its saying the circuit is at fault. So I would assume the wiring is bad or something. But I am at lost on it.

Clogged catalytic convertors will not cause this code. it is for a circuit fault, and from the sound of it, it is a hard fault. (meaning it is occuring right now.) it is also for the left side downstream sensor. (the front bank of cylinders) check all the connectors between the sensor and the pcm. A good place to start is the three connectors on the passenger side near the rear of the engine compartment attached to the engine. I've seen these come loose more times than I can count. You can also check the reisistance of the wiring between the sensor and pcm. If the wiring checks out ok, and the sensor is capable of generating a voltage of about .9 volts during a rich condition, the pcm is at fault. 99 times out of 100 the problem lies outside the pcm, however. If you can't find the circuit fault, try overlaying the harness. Run two wires from the sensor to the pcm along the factory harness. Use some convolute tubing if you can find some. Do not, however, solder the wires. (use crimp splices and heat shrink tubing) This setup draws air around the small spaces between the stranded wire from the pcm down to the sensor and uses this air to compare against the oxygen content of the exhaust. Good luck.

Remember that 96 models are affected by Ford's choice of improper wire insulation that will turn brittle and start falling off--so inspect the wires carefully.

I read the brittle wire recall thing. Ford told me because my car was wrecked that it doesnt qualify for any of the extended warranties on the wiring, front fans, or anything. I feel this is wrong since the car was barely even wrecked. My grandparents hit a dog and it made the airbags come out. It just tore up the front fascia where the foglights were and such. No structure damage or anything like that. But the airbags being deployed caused the insurance company to total it. My grandparents then bought it back and had new airbags installed and a new front fascia and had the whole car repainted. I should call ford and complain I guess, But I doubt it would do any good.

Ill check the wiring connectors. When I checked them before I didnt run into any connectors. I might have been tracing the wrong thing.

Blaze

I forgot to add that the Exhaust shop here has a machine that checks backpressure in the exhaust and it showed that my convertors are not plugged. Its pretty neat the way it works. I had this checked because I felt that it could be a problem. The guy told me that if I dont fix the rich running condition they will plug up. He said the sulfur smell is the convertors eating the unburnt gas form the rich running engine.

Thanks for all your help

Blaze