O2 sensor problems

[lummy]

Hey everyone,
I went to finally get my Hoe smogged today but ran into a couple of snags.

First, the SES light is broken or disabled. The tech was telling me that it should light when you turn the car on. I know The PO did some "creative" wiring since the dome lights don't come on when the door is opened. I took a look at it and they had cut the wires behind the switch
I'm hoping that the bulb is just blown but how much of a b*tch is that going to be to get behind the dash to find out?
If that's not the case, any other suggestions on what to look for?

The other problems are that it threw 4 codes. The first, p1345, I believe is because I had the dizzy off a tooth or two when I took it out to replace the intake manifold gasket. I did reset it to the correct timing after 3 or 4 days.

The other 3 all have to do with O2 sensors, p0141,p0155, and p0161. Is there anything else that might cause all 3 to error? I could replace them but at $70 a pop, that gets expensive quick.
I did have the Y pipe out when I upgraded to the 4l80e. I unscrewed them out of the pipe and left them hanging. They did get some wd40 on them (quite a bit actually) during that adventure.

Any suggestions?

 

[SunlitComet]

The instrument cluster with the light is held down with four hex screws once you unsnap the bezel trim and remove it.

P1345 means the crank/cam sensor is out of alignment. you will need a scanner that reads CAM_RETARD to realign it. If it was off a tooth or two you would know without a code. The tolerance of the alignment is only +-2.0 degrees. It does not take much. Raise the engine speed to 1000(2000 on '99+)rpm when checking and adjusting setting.

With the key on make sure you have 12v power on pink wire at each O2 connector. Those codes are from O2 sensor heater failures all supplied by fuse labelled "ENG 1" 20 amp in the under hood block.if power is at each one then replace all four of them.

---------- Post added at 05:19 PM ---------- Previous post was at 05:16 PM ----------

Unplug battery when actually doing replacement and give it a fresh start with 10 miles of street and highway driving. If all is well the built-in emissions monitors will all go green and the smog shop will see it is ready to pass gas.

 

[lummy]

Cool, thanks for the info. I'll test the sensor's for voltage and go from there. It was only 3 of the 4, would you replace all 4 tho? Bank 1, sensor 1 didn't throw a code.

As for the p1345, I'm sure I was off a tooth. The truck was hard as hell to start. Once I got it started, it ran decently believe it or not. At the time, I thought It might have a fuel leak , the fuel pressure regulator going bad, the distributor being off a tooth or worse, one of the fuel injectors.
Before I tore back into the manifold, I wanted to rule out the timing, so I redid the dizzy by setting cyl1 to TDC. She started right up and has been purring since then.

Sounds like the dash isn't too bad, here's hoping it's just a bulb. TBH, I was wondering why I didn't get an SES when the dizzy was off which is why I was leaning towards fuel. Guess I know why now

BTW, we have almost the same hoe If you do a double take on Rte 4, it's probably me

The instrument cluster with the light is held down with four hex screws once you unsnap the bezel trim and remove it.

P1345 means the crank/cam sensor is out of alignment. you will need a scanner that reads CAM_RETARD to realign it. If it was off a tooth or two you would know without a code. The tolerance of the alignment is only +-2.0 degrees. It does not take much. Raise the engine speed to 1000(2000 on '99+)rpm when checking and adjusting setting.

With the key on make sure you have 12v power on pink wire at each O2 connector. Those codes are from O2 sensor heater failures all supplied by fuse labelled "ENG 1" 20 amp in the under hood block.if power is at each one then replace all four of them.

---------- Post added at 05:19 PM ---------- Previous post was at 05:16 PM ----------

Unplug battery when actually doing replacement and give it a fresh start with 10 miles of street and highway driving. If all is well the built-in emissions monitors will all go green and the smog shop will see it is ready to pass gas.

 

[SunlitComet]

I understand one sensor did not malfunction but if it turns out three sensors are fried you might not want to leave a old one in there especially on that has control over fuel ratio's and fuel trims. what if that one was shorting internally and killing the voltage to the others? If three have to be done then do the forth as well.

 

[lummy]

gotcha, that makes sense.

On a related note, anyone have an opinion on the O2 sensors listed on rockauto? They're half the price than the local OReilly's or Autozone. Any brands you'd recommend or one not to use? I'd likely go with the NTK's
It's also interesting that some of the O2 sensors listed specify which trans they're to go with. Nothing I read about 4l80e swaps mentioned changing the O2 sensors so I'm guessing it has something to do with clearance?

 

[96ProCompTahoe]

i have a bank 2 upstream sensor thats burned out, ordering a bosch o2 sensor from rock auto. good $12 less than the cheapest local price and thats after shipping.

between me and my dad we have ordered quite a bit of parts from rockauto and never had any problems. always had good luck with bosch parts as well.

 

[SunlitComet]

Bosch is the defacto standard in O2 sensors.

---------- Post added at 10:53 AM ---------- Previous post was at 10:51 AM ----------

Amazon bosch sensors go for about $35 for the fronts on the 4l60e units.

 

[lummy]

I checked the 2 downstream sensors and both are giving me 12v. I think it's safe to assume I'm replacing all 4. Thanks for the help.

The bulb was good for the SES but no light. I had the bright idea to run 2 wires from the "Check Guages" light to the SES to at least get it to light. Both lit but wouldn't turn off. Changed it over the battery light and same thing. Oddly enough tho, after I pulled out the cables, the SES light works but not the check guages, nor battery light. Bulbs aren't burnt. Guessing I burnt a fuse someplace under the dash.

That's what I get for trying to be smart

 

[SunlitComet]

Instrument Cluster
Electrical Diagrams

Notes

Gauges & I/panel Illumination

Notes

Warning Lamps & Speedometer

 

[lummy]

Dude... You're amazing!!