DII Fault Codes!! = O2 Sensor Issue

[Brian McVickers]

Lucky me the Check Engine Soon light came on this morning! :Wow1:

I stopped at AutoZone and they pulled the codes for me. I then checked online to translate them. Here is what I found:

P0154
O2 sensor circuit no activity detected (bank 2, sensor 1) 
Front sensor RH bank open circuit

P0155
O2 sensor heater circuit malfunction (bank 2, sensor 1) 
Front sensor heater RH bank - short/open circuit

P0300
Random/multiple cylinder excess emissions detected. Excess emissions detected on more than one cylinder

P0302 
Cylinder 2 misfire detected. Injector 2 excess emissions/catalyst damaging level of misfire

P0304
Cylinder 4 misfire detected. Injector 4 excess emissions/catalyst damaging level of misfire

P0306
Cylinder 6 misfire detected. Injector 6 excess emissions/catalyst damaging level of misfire

P0308
Cylinder 8 misfire detected. Injector 8 excess emissions/catalyst damaging level of misfire

P1300
Random/multiple cylinder misfire detected. Catalyst damaging level of misfire on more than one cylinder

From what I can tell the most significant code is the P0154 indicating a bad RH Front O2 Sensor. I think all the other codes are secondary problems resulting from the bad sensor, but tell me if I am wrong.

A bit of history:
About three months ago I noticed a change in the pitch of the engine's sound. Very subtle, so subtle I thought I was hearing things. The noice is an airy sound, very difficult to describe, a higher pitch than normal. I thought little of it but then noticed once that it went away and then came back after starting and stopping the engine. Meanwhile the engine ran just fine with good power and normal mpg.

About a week after that the Check Engine Light came on. I never pulled the codes but after it was on for about two days it went away.

Then about a month ago I did a 1200+ mile trip with no issues until the end. I was on a dirt two-track in the rain bouncing around a bit with lots of water splash from the trail's puddles, 5-10mph the whole time. After about an hour the Check Engine Light (CEL) came on, started flashing and the engine stumbled. The CEL eventually went solid. I was able to turn the engine off and on with no issue, a little stumble right when I turned it back on but then smooth running. I drove home 400+ miles at highway speed with the CEL on but no other issues.

The next day I had the codes read, 9 total, and they had to do with O2 sensor. The codes were not cleared with the code reader but by the end of the day they had cleared themselves and the CEL went off.

Three weeks later now the CEL is back on with the codes shown above. There is no stumble in the engine but the MPG is down a bit from normal.

--- So -- Any recommendations?
Replace the O2 Sensor?
Replace more than one O2 Sensor?
Try to clean the connections first?
Other?

Thanks
Brian

 

[R_Lefebvre]

Just a guess, but I'd think the presence of P0154 and P0155 simultaneously might suggest you have a wiring problem. The sensor is disconnected, or the wiring harness got damaged. Or the sensor got completely destroyed for some reason. Those two circuits are seperate, but built into the same sensor, and the same wiring pigtail.

 

[Brian McVickers]

Thanks Rob,
Do you know where it is located exactly.

Sounds like it needs to be inspected at the sensor and connection ends as well as along the wiring.

Regards,
Brian

 

[R_Lefebvre]

Well, you're looking at the sensor that is in front of the cat on the RH side of the truck. Just crawl under and you'll see it. The bung is welded in on the upper surface of the pipe. The wire pigtail should travel upwards and basically is squeazed between the bellhousing and the body. The connector should be clipped to a bracket that is bolted to the bellhousing. It's a really tight squeaze in there, bring a light. I can imagine that wire could be pinched between the powertrain and the body, or damaged by a stick or something. Or melted. I'm just guessing there's something obviously wrong with the wires or the sensor itself, like it got smashed, for both those codes to come on together. Then, everything else is probably a result of that.

 

[Brian McVickers]

Ok, thanks.
I found it.
There is a hole chaffed into the outer sheath which holds the three or four wires in there. I could not see an damage to the wires themselves but may need to pull the intire assembly off to fully inspect.

I aslo found this interesting. This picture from RAVE shos that the RH sensors are on the side with the round cat but my vehicle has the elongated cat on the RH passenger side.

 

[R_Lefebvre]

I think that image is mirrored for some reason. Just from memory. But you can see in this picture my round cat is on the LHS. It's hard to make out what's going on with the pipes, but I think mine is the same as yours.

 

[Brian McVickers]

Ok,
As long as it all converts properly that the Right Hand Side is the same as the Passenger side!