Oxygen sensor fuse keeps blowing.* solved (burned wires)

GaryB · Post by **GaryB** » Sat Feb 07, 2009 1:07 pm

Kinda stuck on this one and need some help. My truck started running really rough last night. Feels like it running on 3 cylinders. It seems like it wants to stall when I stop and it has VERY little power because its running so rough. I have a 2002 GMC Sonoma Crew with 175k miles. The only mod is a K&N filter instead of paper.

So, I wend to the local parts store and they pulled the codes:
P0101, P0128, P0135, P0137, P0138, P0141, P0155, P0300, P0327. YIKES!
Also getting a flashing SES when I try to drive it in the condition its in.

I keep blowing the O2 sensor fuse (20amp) also. I think there may be a short somewhere, but I have no idea where to look.

Also, maybe coincidence, but my alternater just went too. So far, I have replaced, PCV, alternator, bank 1 upstream O2 sensor, and thermostat.

The problem persists.

Any help would be appreciated!

I do want to say that this site is simply AWESOME, and has helped me on numerous occasions over the last six years that I've had my Crew. Thank you.

Post by **HenryJ** » Sat Feb 07, 2009 1:24 pm

I am not sure why the fuse is blowing. Look for a pinched wire under the truck somewhere.

All the codes you have could be related to the low voltage problem a bad alternator and battery cause.
The bad alternator can take out a battery quickly and the reverse is true as well. Make darn sure that the battery is fully charged with a battery charger.
Pull both battery cables to clear the PCM and reset the start sequence. Basically start over with a clean slate.

While you are waiting for all the stored energy to drain, check the ignition components. The cap , rotor and spark plugs. Replace as needed. If it has been a while since a fuel filter change, do that too. Add a dose of injector cleaner to the fuel tank too. I like to do that every other engine oil change. Now pull the MAFS and clean it.
Once all that is taken care of you can reconnect the battery and fire it up. Check to make sure the voltage comes up to about 14 where it should. Hopefully it will run like a top. If it does not, at least we have a fresh set of codes with the proper voltages being received.

roadrunner · Post by **roadrunner** » Sat Feb 07, 2009 1:42 pm

P0101: Clean your Mas air flow sensor with cleaner specifically for it or very carefully with alcohol and a q-tip. Do this first and see how truck runs afterward. This information on how to can be found on this site with a quick search.
P0128: relates to run-time too long with engine temp too low. Install new 195* thermostat. If code was not cleared after replacement of old stat or colder stat was installed it's a residual code or caused by new colder than stock stat. Also discussed at length on this site.
If you didn't clear codes after replacing bank 1 sensor 1 then some of these may be residual codes. If you did clear it then I would look there for your shorted wires. It is possible you may have gotten a defective new sensor as well. Since you have multiple codes for the downstream sensor as well inspect wiring carefully in that area as well. If that wiring is okay then you probably need to replace that sensor as well. (All 3 sensors are the same)
Before getting excited about P0300 and P0327 see how it runs after cleaning MAF sensor and also you did not say how long since plugs, wires, fuel filter, etc have been replaced. Additionally a recent fill of bad gas can be a culprit. Checking fuel pressure as well would help diagnose.
With so many codes you're going to have to attack them one at a time till it runs better then recheck for more codes and re-attack etc etc. We will all help as much as possible.

F9K9 · Post by **F9K9** » Sat Feb 07, 2009 2:27 pm

HenryJ wrote:..............If it does not, at least we have a fresh set of codes with the proper voltages being received.

. Best to check this out first and get a fresh set of codes.

GaryB · Post by **GaryB** » Sat Feb 07, 2009 4:04 pm

Thanks for the quick replies! I am taking your advice and doing the things you recommend. Hopefully my next post will be to inform you my findings and what exactly caused the major error.

Post by **HenryJ** » Sat Feb 07, 2009 4:19 pm

Be careful of the plastic distributor housing: Check this out first: Plastic Distributor warning

04crewvt · Post by **04crewvt** » Sat Feb 07, 2009 8:41 pm

Any chance you just cleaned and re-oiled the K&N filter? Some of those codes can set if too much oil is on the filter and it is pulled into the MAF and intake.

GaryB · Post by **GaryB** » Sun Feb 08, 2009 11:15 am

It seems to be better now. I found the oxegen sensor wiring harness for the bank 2 (passenger) side pre-cat sensor and post cat sensor absolutely burnt to a crisp. I figured it got too close the exhaust manifold. This was causing the o2 fuse to blow. I spliced in eight more wires and reinstalled the harness.

I also did the following:
1. Cleaned the MAF sendor with alcohol
2. Cleaned the air filter
3. changed the thermostat (it has been sticking open for several months)
4. New PCV valve.
5. Tried to change the fuel filter but couldn't get it off. I'll get that done soon by the pros.

Truck is running great, no SES.

Thanks again for all of your advice! This site is simply awesome! You know, I even used this site to research the Sonoma Crew even before I bought it new in 2002. I plan on keeping this truck until Mother Earth takes her back.

roadrunner · Post by **roadrunner** » Sun Feb 08, 2009 12:57 pm

Glad we could help. You might want to wrap those wires with some heat resistant loom protector. Much the same thing as is used to protect plug wires around headers.

Post by **HenryJ** » Sun Feb 08, 2009 1:04 pm

Good to hear. Glad you are here to share your experiences too. We all learn from stuff like this.