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Auzboy · 05-22-2014, 10:26 PM

Hello, I am new to this forum and having read many other posts thought I might get some good ideas here.
Today we were driving the RV (2004 Holiday Rambler 37PCD) with 8.1 GM gas on workhorse chassis, Alllison Transmission, when the check engine light came on for no apparent reason. I stopped and checked fluid levels, topped off oil (was only 1/2 liter down from full) and couldn't find anything obviously wrong. The temperature was dead on center indicating normal. No other indicators showed faults. I have a code reader (not with me of course, its at home) but I'm guessing its something like a partly plugged fuel filter, bad O2 sensor or something of that nature. As its still runs fine, no lose of power or untoward noises, I'm wondering on advice as to whether should I continue home and get it to my favorite mechanic or run in quick to nearest mechanic. Any thoughts? Currently in Helena MT north bound to Alberta.

JALTAR · 05-22-2014, 10:36 PM

Quote:

Originally Posted by Auzboy

Hello, I am new to this forum and having read many other posts thought I might get some good ideas here.
Today we were driving the RV (2004 Holiday Rambler 37PCD) with 8.1 GM gas on workhorse chassis, Alllison Transmission, when the check engine light came on for no apparent reason. I stopped and checked fluid levels, topped off oil (was only 1/2 liter down from full) and couldn't find anything obviously wrong. The temperature was dead on center indicating normal. No other indicators showed faults. I have a code reader (not with me of course, its at home) but I'm guessing its something like a partly plugged fuel filter, bad O2 sensor or something of that nature. As its still runs fine, no lose of power or untoward noises, I'm wondering on advice as to whether should I continue home and get it to my favorite mechanic or run in quick to nearest mechanic. Any thoughts? Currently in Helena MT north bound to Alberta.

I just had a similar issue when driving from TX to Canada in our new RV. I checked everything as you did all was good. I kept trucking and when i got home hooked it up to my code reader and it was the O2 sensor. Only thing you missed was maybe your gas cap wasn't on tight?? If you think it was the fuel cap...un-hook your battery for 5min and that will reset it, after 3-5 ignition starts, it problem still exists then you will have to wait till you get to your code reader. Good luck!

Scarab0088 · 05-22-2014, 11:42 PM

Gas cap is a real thing for the Check Engine light and it will show intermittently. If you have an aftermarket locking cap, you might need to dump it.

Best luck

Arch Hoagland · 05-22-2014, 11:57 PM

I had intermittent check engine lights for the better part of a year. O2 sensor was the code...replaced the sensor....no help.

Turned out my MAF (Mass Air Flow) sensor was dirty. Cleaned it and replaced the air filter and the problem was solved.

You really need to read the code and come back on here with the code you are getting.

As long as you are running fine I'd head on home and get your code reader or go to a O"Reilly's and they will read your code for free.

I have one of these attached all the time now on my dash:
UltraGauge OBDII Scan tool & Information Center

zorro2kita · 05-23-2014, 02:59 PM

Agree with previous post - had similiar situation in AK last summer - loss of power (intermittent) - check engine light finally came on - found shop that had the right code reader - Repair consisted on New Mass Air Fl0w Sensor, O2 sensor, air filter and fuel filter and clean throttle plate -

Has run flawless since last August !!

Need the codes read !!

Auzboy · 05-24-2014, 08:10 PM

Thanks to all of the Members for their input. I tried JALTAR's suggestion to disconnect the battery but didn't affect any change. Arch Hoagland's suggestion to go to O'Reilly's worked out well, there was a location nearby, they loaned me the reader and I got a code reading of P0131 and they gave me a print out from their computer with suggestions of a probable cause based on a GM truck engine (which it is) and the mostly likley cause was related to the O2 sensor. I reset the codes and the check engine light so far remains out 450 miles later. When I get back I'll crawl under the RV and check it out.
Thanks again to everyone for their input, next trip my code reader gets added to my ever growing collection of tools I take with me.

Arch Hoagland · 05-25-2014, 12:17 AM

I fought the P0131 battle for about a year. Very intermittent. i bought a new O2 sensor for about $75 at Napa and installed it myself. That one is on the passenger side exhaust pipe prior to the muffler. Easy to get to. It didn't cure the problem.

You need a special socket to remove the sensor and you'll have to make a extender for your wrench to get enough torque to loosen the sensor.

However I suspect the code is telling you that you have an air/fuel mixture problem, which is why the sensor is there.

In my case the MAF sensor was dirty and I needed another air filter. The MAF sensor is located in the passenger side wheel well and connects to the air filter box. Check you air filter...a new one from Walmart is about $15.

mx08453 · 05-27-2014, 07:53 PM

Arch,
What else can you tell me about the special wrench? I have to replace mine. Txs

Arch Hoagland · 05-27-2014, 11:30 PM

mx08453..........

Here is one:

7/8 in. Oxygen Sensor Socket

Here's another

List: Socket - Oxygen Sensor | O'Reilly Auto Parts

Most auto parts carry them.

Where are you going to buy your sensor and how do you know it is bad? There are different part numbers for it.

Also you will need to soak your old sensor with PB Blaster for a day or so as it is really in there tight. I made an extension for my wrench with a piece of pipe so I could get some leverage on it.

The hardest part was figuring out how the electrical clip worked.

edgray · 05-28-2014, 07:45 AM

Quote:

Originally Posted by Arch Hoagland

I fought the P0131 battle for about a year. Very intermittent. i bought a new O2 sensor for about $75 at Napa and installed it myself. That one is on the passenger side exhaust pipe prior to the muffler. Easy to get to. It didn't cure the problem...........

In my case the MAF sensor was dirty and I needed another air filter. The MAF sensor is located in the passenger side wheel well and connects to the air filter box. Check you air filter...a new one from Walmart is about $15.

Good info, ARCH. Often us DIYers spend $$ changing out parts that are only the messenger, while the root cause goes undetermined. Cleaning the MAF and replacing the air filter is easier and much cheaper, as you found out. THANKS for posting the correct solution. Ed

JALTAR · 05-28-2014, 08:28 AM

I am taking mine in this week for the O2 sensor, warranty work. But good to know the other solutions if it does not change. Thanks for all the info. You guys are awesome!! Keep the mods and solutions coming! I'm still a rookie so in time I may be able to contribute!

Here is the Code I got...

Oemtech · 05-28-2014, 11:43 AM

Bad O2 Sensor would be my guess.

89sandman · 05-29-2014, 11:05 PM

Quote:

Originally Posted by JALTAR

I am taking mine in this week for the O2 sensor, warranty work. But good to know the other solutions if it does not change. Thanks for all the info. You guys are awesome!! Keep the mods and solutions coming! I'm still a rookie so in time I may be able to contribute!

Here is the Code I got...

bank one is the side of the engine which has the number 1 cylinder, sensor 2 is the down stream sensor, after the converter. the heater circuit heats the sensor so it comes on line faster reducing emissions. you may have a fuse in one of your fuse boxes for it, if the fuse is good the sensor will need to be replaced. for you guys changing oxygen sensors and not fixing the problem if your 97 and newer you have more than one. the 131 code is for the upstream, before converter, on the #1 cylinder side.

stink · 05-29-2014, 11:28 PM

30 years as an auto tech I have only seen three bad o2 sensors. Lots more for contamination with coolant. O2 codes generally point to a problem with fuel/air control like a mas air flow. A vacuum leak can also effect mixture control. I usually do not like to dits a product but I have replaced lots of mas airflow meters with contamination while using a K&N air filter. The oil in the filter contaminats the sensor causing it to underestimate the air entering the engine thus causing a lean condition thus setting an O2 code for lean condition. The PCM also monitors the fuel system for leaks thus setting a code for the gas cap. This code will be "evap slow leak". A leak in a vaper hose can also set this code.