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Troubleshooting Misfire and Bank 1 Sensor Errors

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whathasnt

New member
This is my first post. I just got my first GP and it's got the 3100 in it.

It has a problem with bogging down a few minutes after driving. It gets 5 engine codes (P0135, P0141, P0131, P1133, P0300)

All of the codes come back to bank 1 sensor and misfires.

I have replaced the entire exhaust system, spark plugs, wires, and a general tune up.

My next step was checking for a vacuum leak, which unfortunately I've never done before. Any suggestions?

I appreciate any help or guidance. Thanks
 


Please post at least the names of the codes to help us help you.

Bank 1 in a GM FWD V6 mearly means the single 02 sensor in the one exhaust pipe (after they combine) is seeing an issue. Therefore there's an issue with the motor.

Have you scanned while driving to find the cylinder with the issue?
 
P0135 O2 sensor heating circuit
P0141 O2 sensor heating circuit
P0131 O2 sensor low voltage
P1133 HO2S switch from lean to rich - not enough times

Sounds like the upstream O2 sensor is not plugged in.
 
No, I haven't scanned while driving. I still need to get a scanner. Both O2 plugs are plugged in. I replaced the bank 1 sensor and just got done reinstalling the second after replacing the exhaust.

I was trying to check for vacuum leaks, but feel extremely stupid as I'm not sure where to be looking and had trouble finding a diagram. I bought some carb cleaner to try and find it, but no luck last night.
 
Disconnect the upstream O2 sensor and turn the key to the "ON" positon. Make sure you have supply voltage on the leads inside the connector that comes from the PCM. There should be two supplies, one for the sensor and one for the heater. This is quick and easy and you'll rest assured it's not something stupid.
 


I checked those and I'm getting 11.7 volts roughly on the one connection and 390mv roughly on the second. I don't know if these are right.

Still struggling to find something. I tried blowing smoke in near the intake and couldn't find any leaks that way and went to town with the carb cleaner again and still nothing.

I really need to get this fixed and starting to think it might be time to drop it off at the local garage at least for a diagnosis so I can stop guessing unless anybody has any other tips?
 
I have no idea. I just got it and it was a mechanics special. I've been trying to solve it for 2 weeks. Anyway I can check if there's an issue with that?
 
whathasnt said:
I checked those and I'm getting 11.7 volts roughly on the one connection and 390mv roughly on the second. I don't know if these are right.

Still struggling to find something. I tried blowing smoke in near the intake and couldn't find any leaks that way and went to town with the carb cleaner again and still nothing.

I really need to get this fixed and starting to think it might be time to drop it off at the local garage at least for a diagnosis so I can stop guessing unless anybody has any other tips?
Click to expand...


Yea, I guess that's right for a two wire sensor. The 12V is for the heater/supply and the other is for the return signal back to the PCM.

The PCM is not telling you that its running lean. It says that there is something wrong with the circuit itself. The PCM is not getting any feedback from the circuit whatsoever.

P0135 O2 sensor heating circuit
P0141 O2 sensor heating circuit
P0131 O2 sensor low voltage
P1133 HO2S switch from lean to rich - not enough times

This would indicate wiring, O2 sensor or something wrong with the PCM. A real-time scan will greatly improve your ability to diagnose this problem.
 


Well, I've got a little more direction.

I was reading around some other posts and got the idea to disconnect the MAF sensor. Instantly it runs great and the issues are gone.

Tomorrow I'm going to take all of that apart and clean it and see if it makes a difference, but it's nice to know that although it's running rich at least I can get it to work when I need to as I work to find the exact issue.
 
I also have an ODB scan tool on it's way. Should be here Monday or Tuesday and then I'll get some realtime info with it acting up to help narrow it down.
 
Wow, that's great. I'll have to remember this one. It was running so rich that the O2 sensor wasn't even within it's operating perameters. Makes sense. My next guess would have been a dead injector causing the same symptoms. I've actually seen this before.

Yea man, clean that MAF and see what happens. Your local auto store has the MAF cleaner on the shelf.
 
Well, I got a solution. I thought it was clean until I got the MAF cleaner and read the directions. I finally completely disassembled it and found quite the build up on one side. I used the cleaner and made it spotless again.

After cleaning it, the car works perfect with the MAF plugged back in. I can't believe it was an $8 fix.

Thanks for all the tips.
 


O2 Sensor P codes

Hey, everyone was a big help with fixing my major issue with my engine a few days ago and I thought all was good, but now it's spitting O2 sensor codes that I still need to get resolved. It's making the engine run lean and randomly stalling.

The codes are P0131 - Incorrect voltage to Bank 1 Sensor and P0135 for the Bank 1 heater. Anyone have any suggestions on a resolution? I all ready replaced the sensor itself.

I checked the voltages from the the voltage is roughly 390mV when it is supposed to be 175mV.

The documentation that says it should be 175mV which would explain it running lean. Now I just have to determine why.
 
After the car warms up does it still stall? Reason I'm asking; if heating circuit is bad it takes a few minutes for the sensor to get up to operating temperature (600 degrees F). If the heater is good then it takes much less time to heat up, like 30 seconds or something.
 
Sorry about that with the split thread. Will keep them together in the future.

And yes, it will stall after it has warmed up. My girlfriend was driving it yesterday and it's about 5 - 10 miles into town and it was stalling in town.

I got a better app to use with my scanner so hopefully I can get more info out of it tonight or tomorrow
 
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