Well guys, I know there have been plenty of O2 Sensor problems discussed here, but I couldn't find anything that would help me out. About 2 weeks ago I got a CEL. We had another car in the shop getting serviced so I just had the mechanic stick his scanner on it. It showed up that Bank 1 and Bank 2 O2 sensors were indicating too rich of fuel. He said that once in awhile they will get bumped the wrong way and kick on, he said he would reset it and if it came back on, then something is probably wrong. Well yesterday it came back on. I put my tuner on it this time and I got what I think is the same thing. There are two codes. P1132 and P1151. From the book it says that H02 sensors S11 and S21 are indicating rich. What can I try to fix this? Do you think that they would both mysteriously quit at the same time? I'm thinking not, but there has not been any change in driving conditions, so it seems that it may be just a sensor. Let me know what you guys think. Thanks

 

P1132: bank 1 Rich
P1151: bank 2 Lean

These are for the front oxygen sensors, bank 1 is pass side, bank 2 is driver side.

O2 sensor codes can be difficult to diagnose because it is often not clear whether the sensor itself is the cause or just reporting another problem.

The fact that one bank is lean and the other is rich would indicate that it is probably not something common to both like the MAF sensor.

How many miles on the odo? Things that can contribute to the death of an O2 sensor are leaded fuel, common silicone sealer fumes, excessively high temperatures and high miles.

 

I could have sworn that I read that they were both reading rich, so I went back out and found out why I thought so. There are three error codes, and I looked up only two in the book and wrote down two different ones to make my first post. So the three codes are P1132, P1151, AND P1152. Seems crazy that the same sensor could be reading lean and rich?

I only have 58,000 miles on the odo, so I wouldn't think the miles would be the problem. I do run ethanol, which I was told by the ford mechanic that it was fine, but would that cause this problem? Sorry about the confusion on the codes.

 

Ethanol is safe.

All three of those codes are for a lack of switching, meaning that the sensor is hanging too long on either one side or the other of stoichiometry (chemically ideal air/fuel ratio). A normal truck switches every second or so when in closed loop mode but this gets longer as the sensors age. A lack of switching code can mean that the sensors are no longer working at all or are reacting too slowly.

Have you used silicone sealer ANYWHERE on the truck but especially on the engine or near the air intake? Except for the special O2 sensor "safe" type, silicone sealer will poison the sensors, especially if used as a gasket sealer or on or near the filter housing.

 

I haven't used any silcon sealer anywhere at all. I'm taking the truck in tomorrow to see what they can come up with.