Oxygen sensor

[DaveW79]

My 95 cougar with 4.6L has constant bank 1 oxygen sensor 2 and bank 2 oxygen sensor 2 error codes causing check engine. OBDII says they're not heating. Needless to say, they've both been changed and the problem persists. I don't understand Haynes' Manual wiring diagram. Desparately need help with this one.

[baylensman]

check the connections at the O2 sensor ford cars notorius for having loose or bad connections at these points. Also turn radio on and pull the positive cable on the battery leave off for 10 minutes. Pull the air tube and spray carb cleaner in throttle body (don't touch the 2 little wires) reconnect battery turn off radio start car engine should hunt for new idle for a few minutes (and maybe the next few times it is started) the computer may not be synching "old" settings with "new" O2 sensors.

[95 cougar]

What kind of symptoms were you having? I have a 95 cougar v8 and have slugish acceleration.

[fone_fanatic]

i have a 99 cougar with the same obdII fault codes, took the sensors out and tested them, they work fine but fault codes still on, replaced them and fault codes are still on. took them to a shop and they said its because i have an aftermarket exhaust system on it. so i just gave up, still have the obdII light and the maintance light on..

[baylensman]

thnks guys read this thread and replied now i'm having the same problem with a 97 XR7 I've cleared the codes with a professional scanner then monitered the operation and get clean voltages fromall 4 sensors, and all values are in the response curve. then all of a sudden the service engine light comes on the code is for a faulty sensor, check the sensor again and its clean. driving me nuts. car is now bone stock, i took off the K&N filter just to see if too much air was causing a cold sensor but no go still have the problem, will put the car on thelift tommorrow and check all the connector right back to the eec unit and try to isolate and will report back if i find something

[baylensman]

JUST A QUICK UPDATE. CAR DIDN'T START ONE DAY LAST WEEK JUST PLAIN DEAD. checked it out problem was loose negative cable on battery. clean and tightend the cable and since then no codes thrown under heavy usage, looks like the O2 sensor was getting a bad ground at start up and throwing the code, so check all of the grounds see if this helps
walt