Service Engine Soon light

Finally got to bring our new-to-us 2002 Winnebago Adventurer 35U home today after waiting for 3 weeks to have the title cleared.  Got 20 miles down the road and the Service Engine Soon light came on and stayed on steady.  This is a Workhorse W22 chassis with the 8.1. V8 Vortec Chevy engine. Seller said the light came on once when he was coming back from Texas. It went out before he reached home.  Local auto shop checked and could find no problems.  The coach has not been driven more than 16 miles in the last two years.  Debating whether it is worth my time to buy an OBD II scanner to look for the problem. Lots of scanners on eBay but the only ones that let you choose engine say their scanner will not work.  Previous owner says he figured it was a cracked seal on the gas cap and bought a new one from Winnebago dealer.  This is first time problem has reoccured.  The fuel tank is full and I am wondering if stale fuel may be the problem or is an oxygen sensor is bad.  Others say it takes an OBD II to reset the light and it may be worth it to buy my own to avoid further expensive scans by dealers or local mechanics.  Any thoughts?  Thanks.

If you can stop by almost any autoparts store, they will hook their OBD-II scanner up, read the codes, and reset them.
I would recommend getting your own though.
Bob

if you are going to do the repairs in the future yourself, you need a scanner. You will also need a list of codes to know what they are telling you. I just had a 02 sensor go out in my chevy truck and my scanner told me witch one it was. I bought a Mac scanner off of ebay a year or so ago and it serves me well. I also bought a set of service manuals for my chassis, they've already paid for themselves.

92GA said:

if you are going to do the repairs in the future yourself, you need a scanner. You will also need a list of codes to know what they are telling you. I just had a 02 sensor go out in my chevy truck and my scanner told me witch one it was. I bought a Mac scanner off of ebay a year or so ago and it serves me well. I also bought a set of service manuals for my chassis, they've already paid for themselves.

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Everybody here has the list of OBD2 codes. And the best list of all. Simply search the OBD2 code in your browser and find your make of vehicle where the code has shown up. It will tell you what to check and how to fix it and such. Here is an example.

On any OBD2 code you can get as much info. as you want on the web (and then some).

Anyway, my best advice is to not ever guess why a MIL (Check Engine Light) is on. It can get extremly confusing as they don't all work the same way. Some will stay latched on even after the problem is cleared. Others will take several restarts and so many miles just to set the code when the real problem came days before the MIL was on. Others will activate the MIL right away. Some will go off only after so many restarts. So in many cases, you can think it's fixed when it is not. You must get the OBD2 code numbers read. In most cases, any cheap $30.00 OBD2 reader will read your code, but there are some exceptions with the less common OBD2 codes.

Your check engine lite is on and they found no problem? They couldn't have scanned it! OBD2 will give a code if CEL is on, heck it'll hold a history if the CEL self clears. Find a real shop with lights inside.

Bill

driftless shifter said:

Your check engine lite is on and they found no problem? They couldn't have scanned it! OBD2 will give a code if CEL is on, heck it'll hold a history if the CEL self clears. Find a real shop with lights inside.

Bill

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I am just going on the word of the previous owner.  The light cleared (went out) before he completed his trip.  He had it checked by his mechanic and no codes could be found.  He bought a new fuel cap from Winnebago because the old one had a crack in the seal.  The unit has pretty much sat for 2 years and last filled it up about a year ago.  He says he was told NOT to use stabil because ethanol will do the trick.  I don't believe it will so I am wondering about a stale fuel problem but am going to see if my local parts store can do an OBD2 check and maybe sell me a meter that will work on this chassis/engine.  I see lots of them that advertise to work on 96 Chevys and up but when you get into the details of a Workhorse with 8.1L V8 Vortec, it says Will Not Work.  Since it is stored 10 miles from home, I will make a few trips back and forth with it to see if it clears but, like one of the posters said, I still want to know the codes and get the blasted thing reset.  Thanks for all the great responses.

I bought one of these OBD II Scanners: http://www.amazon.com/Autel-MaxiScan-MS300-Diagnostic-Vehicles/dp/B001LHVOVK/ref=sr_1_1?ie=UTF8&qid=1390751220&sr=8-1&keywords=obd+ii+scanner It is easy to use and gives you a code and a book to look it up. If the CEL is on, you will get a code. I am no mechanic, but I like being able to check the code myself before I go to the shop, so I can talk intelligently with the mechanic.

Bill N said:

I am just going on the word of the previous owner.  The light cleared (went out) before he completed his trip.  He had it checked by his mechanic and no codes could be found. 

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It makes no difference if the check engine light clears. The code stays in memory until it is cleared with an  OBD2 reader or battery is disconnected. The previous owner gave you a story that could not have been true, unless  if the battery is disconnected,  which will reset ALL the codes to "not ready" just as does clearing a single code.

BTW, if a single code is cleared, or if the battery is disconnected, you cannot pass a smog test until the vehicle has started from cold start (such as after sitting over night) and then  the vehicle is driven normally for around 50 miles or so. But it won't fail, it just cannot be tested until "ready", which means enough time was given to see if there's still a problem.

I own one of these, which is not much of a OBD2 reader, I  only use it to tell me when the vehicle is ready to be tested after it's been worked on.

-Don-  SSF, CA

Gas is 2 years old? There's your problem. Gasoline does a few things as it ages, it's worse now with alcohol. It loses octane = less energy per gallon, it oxidizes and turns to varnish, and the alcohol attracts and envelopes moisture, turns into goo. I'll bet your exhaust smells a lot like turpentine or old oil base paint.  You have to get rid of the old gas.
My favorite way would be double dose of Seafoam or Techron fuel system cleaner for the approximate gallons in tank. Find your fuel filter(s) and pick up a couple of spares. Drive around in circles, close to home, burn that gas. If engine hiccups head straight home, If hiccuping worsens change filters. Go in circles again, at 1/2 tank, add a name brand of hi-test. I don't know which is truly best anymore, when I was a younger man Mobil had the best additive package for cleaning varnish all the way to the combustion chamber, according to Consumer Reports, using BMW test procedure. Gasoline octane degrades with age, the hi-test will boost the octane level. Don't try any tuning adjusments until you're running a completely fresh tank. After 1/2 tank of hi-test run it as empty as you dare and only put $10 at a time in, a couple times. Get your CEL cleared or diconnect neg battery cable for a minute. Drive another 50-60 miles, if it doesn't come back on it's fixed. Then fill up with fresh gas.....unless you still have CEL/SEL. Then don't fill it, keep it near empty, in case the tank needs to come out.

Local fire deparments around here will take bad gas for residents. Thats the second and least expensive option, you gotta pump it out and bring it in.

The ex$pen$ive option is to drop it at a shop and tell them to fix it. Because it's a haz-mat it cost's $ to dispose of. It's a big too-doo if you've got 80 gallons of gas to get rid of.

Try my method, do laps on a familiar circuit of roads and highway, whatever, stick close to home. If it starts hiccuping and hesitating, change the fuel filters.
Get a manual that covers the year and drive train of a Chevy truck with your GVRW and engine tranny combo. It might look like a 6 wheel dump truck, that will cover the engine and tranny, and fuel system, maybe more.

Bill

DonTom said:

It makes no difference if the check engine light clears. The code stays in memory until it is cleared with an  OBD2 reader or battery is disconnected. The previous owner gave you a story that could not have been true, unless  if the battery is disconnected,  which will reset ALL the codes to "not ready" just as does clearing a single code.



-Don-  SSF, CA

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I think you nailed the reason for no codes Don Tom.  The guy just put a brand new chassis battery in the coach before he put it up for sale so the codes would be gone.  Also Bill was commenting on the old gas. It was actually not 2 years old as I questioned the guy again and he says he filled it up about 8 months ago but what really bothers me is that he keeps giving me this line that HE WAS TOLD (by whom?) NOT to use Stabil because ethanol in the gas would do the trick.  Any fool knows that is not true.  One saving grace is that the thing runs like a scared ape and the Onan also purrs along like a kitten but i will be driving it around the local area anyway to expend some of that gas. I had already put 50 miles on it bringing it home from the sellers house and will be putting some gas treatment in the tank tomorrow to try and stop any further possible varnishing problems (not that I have noticed any yet) and I will be introducing fresh fuel into the tank every time I have a chance.  I will be buying the OBD II for the future no matter how this turns out.  It is just too convenient to plug it in and see what's cooking in the engine department.  Thanks guys.

If budget allows, try to get one of scanners with recording capability. These allow continuous monitoring and capturing of real-time data for transient events, even those that may take multiple events to cause service light to come on. About 1/2 again and up in price. One time only kind of buy.
Bob

Bill N said:

I think you nailed the reason for no codes Don Tom.  The guy just put a brand new chassis battery in the coach before he put it up for sale so the codes would be gone.  Also Bill was commenting on the old gas. It was actually not 2 years old as I questioned the guy again and he says he filled it up about 8 months ago but what really bothers me is that he keeps giving me this line that HE WAS TOLD (by whom?) NOT to use Stabil because ethanol in the gas would do the trick.  Any fool knows that is not true.  One saving grace is that the thing runs like a scared ape and the Onan also purrs along like a kitten but i will be driving it around the local area anyway to expend some of that gas. I had already put 50 miles on it bringing it home from the sellers house and will be putting some gas treatment in the tank tomorrow to try and stop any further possible varnishing problems (not that I have noticed any yet) and I will be introducing fresh fuel into the tank every time I have a chance.  I will be buying the OBD II for the future no matter how this turns out.  It is just too convenient to plug it in and see what's cooking in the engine department.  Thanks guys.

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I am not so sure if Say-Bil does anything as it says right on the bottle "will keep fuel fresh for UP TO one year". Since I have used two year old untreated gasoline several times without any problem, it makes me wonder if the Sta-Bil will last as long as the gasoline. I have  had  bad gas  freshly pumped and old gas work well, so it seems to just be hit and miss. Perhaps depends more on where and how the gasoline  has been stored and the temps, humidity and such before we even see it. No doubt where it is stored will have a lot to do with how long it will last before causing any problems. But at both my Reno home and here in SSF I have had good luck with very old gasoline ( I own more vehicles than I can use all that  often).

If you don't get a MIL (Malfunction Indicator Light) / check engine light after a couple of days of use and a 100 miles or so, after the battery has been disconnected, or any code erased,  it will be best if you forget you ever had it lit. By then, all sensors  whould be "ready" as well as have enough time to report any possible OBD2 problem. But be sure your MIL  is lit when the ignition is on but the engine is NOT running, so you know it can report.

I am curious how well one of these will work. Requires a computer and bluetooth, but perhaps it will show more codes than most other older code scanners with simple software updates in the program running on the computer. I just ordered a couple to play around with at each home.  So I will know if they are any good by next week or so. I already own several OBD2 readers, I can keep one in each of my dozen vehicles. I even a reader  for my newest motorcycle, 2013 Triumph Trophy SE called a DealerTool.

My RV has the ScanGauge 2, which will do the OBD2 codes, tell you when sensors are "not ready" and much more.

-Don-  SSF, CA

bobsharon said:

If budget allows, try to get one of scanners with recording capability. These allow continuous monitoring and capturing of real-time data for transient events, even those that may take multiple events to cause service light to come on. About 1/2 again and up in price. One time only kind of buy.
Bob

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Called "pending codes" in some of my OBD2 scanners and I too have found it very useful for intermittent OBD2 problems.

Without the proper equipment, MIL's can be very confusing to when they really happen and when they are really fixed.

-Don-  SSF, CA

Sta-bil works, been using it for 30 years on my boats and VW's, for winter storage. I always regret skipping it, when I do.

Bill

DonTom said:

  I have  had  bad gas  freshly pumped and old gas work well, so it seems to just be hit and miss. 
-Don-  SSF, CA

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If I have learned nothing in my 74 years, it is to drive away when you see a tanker offloading at a filling station.  Twice in my younger days I ignored that warning sign and wound up with a tank of sludge from the bottom of an underground tank.  It was stirred up by the tanker dumping in new gas as we were merrily pumping the mixed up junk into our car.  Thankfully I noticed the rough running and changed the fuel filter after a hundred or so miles but a station owner warned me about what tanker offloads can do to a tank that has sludge in it (and most do).

Also decided this morning that since I know nothing about the previous uses of the MH, I am going to start from scratch and have a lube/oil/filter change for both the chassis engine as well as the generator.  From that point I will have a starting point of when to change oils and filters.  I have some Camping World coupons that are coming close to expiring and there is one only 20 miles away so I will let them do the work (too old and too cold for me).

Bill, I would look for an independent small garage to look at this for you. Around here our truck  service centers run $135 to 140 per hour for service. Most small garages work for about 1/2 that. I have a 05 chevy truck with 43000 miles and the 02 sensor on bank 2 went out last week when it was -13 degrees. I was able to get it in my buddies garage and we were able to get it changed out, but it wasn't so easy. We had to use a torch to heat the flange to remove the sensor, something that neither of us had to do before. You do need to have someone working on it that has a scanner and knows what the scanner is telling him. My 02 sensor was working then it wasn't, would go back and forth. There are so many codes on obd2,  don't let a guy just start changing parts.

Edit: Removed excessive white space.

Bill N said:

If I have learned nothing in my 74 years, it is to drive away when you see a tanker offloading at a filling station.  Twice in my younger days I ignored that warning sign and wound up with a tank of sludge from the bottom of an underground tank.

Also decided this morning that since I know nothing about the previous uses of the MH, I am going to start from scratch and have a lube/oil/filter change for both the chassis engine as well as the generator. 

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I still refuse to stop @ a gas station when I see a tanker offloading, even though I've been told by reputable sources (friends who own or have owned gas stations), that with the new filtering and monitoring systems in place today, it's not the problem it used to be.  Also, when you pull into the station, the tanker could have just left by another exit, and you just didn't see him go.

Good idea to establish a baseline with fluid changes.  I did that right after I bought mine.  Even though the previous owner told me he had taken care of all of that, and even had records of when he had done it, I'm a skeptical person, and I don't take for gospel anything I can't verify myself.  But even after a LOF, tune-up, and checking all belts and hoses, I still got a code, and the MH broke down on the road, it turned out to be 2 faulty sensors.  But since then, I've had NO problems...knock on wood!

rebelsun said:

Good idea to establish a baseline with fluid changes.

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This message thread must have jinxed me. On the drive up here to Reno, in my 99 Dodge Ram pickup truck, the check engine light came on.  OBD2 code P1757, a code I have never seen before. But it has been years since the tranny fluid has been changed, but that's only perhaps 500 miles or so since than. This truck has been unused and covered for more than the last six months (BTW, the old gasoline still ran the truck as good as fresh).

I erased the code, I will check the fluid to see what it looks like and if I get this code again, I will change the tranny fluid and filter a take a much better look.

The above code can clearly show why these codes cannot ever be guessed at. Get an OBD2 reader. Even the "check engine" light meant to check the tranny, not the engine, in this case.

-Don- Reno, NV

driftless shifter said:

Sta-bil works, been using it for 30 years on my boats and VW's, for winter storage. I always regret skipping it, when I do.

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And I have a couple of unopened bottles of Sta-Bil here. After I read the label, I decided not to use them. They are now years old. I wonder if they are  still good. Anyway, I have been extremely lucky with old gasoline, It's never caused me a problem with untreated gasoline even if more than two years old. However, I do have my limits. I have six year old gasoline in one of my boats. I will drain that and get rid of it some day. And I would still dump that if it had Sta-Bil in it. I won't even try gasoline that old. I will get the fuel  out of the carburetor and such too.

But I did get bad gas "fresh" out of a gas station pump a couple of times but never from my own old untreated gasoline less than three years old.

-Don-  Reno, NV

Well here is an update on my particular SES light.  I pulled the MH out of storage today and on the way home I stopped at an OReilly Auto Parts store and had them read out the Diagnostics on the SES fault.  In 5 seconds, the young man told me it was a code PO327 Knock Sensor Circuit 1, Low Input.  He said they had a part listed at $60 but that it did not specify if it was a #1 or #2 knock sensor.  So I told him I would hold off and check with my expert panel (take a bow guys).  I suspect both sensors are the same, just one on one bank of the engine and the other opposite it. Even the guy at the parts store said that normally a #1 of anything usually corresponds to the side with the #1 cylinder.  Got the description of the fault and it does not sound like a killer but something that should be replaced.  Anybody had any experience with this fault and the Knock sensor replacements.  I doubt that I am capable but I know a couple of local mechanics that could tackle the job.