Service Engine soon light

AzTitan · 05-15-2004, 09:04 PM

yesterday i ran the truck low on fuel to where the gas light came on, filled up to about a half tank. then today after about 40 miles from then my service engine soon light came on and at the same time it seemed like the truck downgeared/gave it gas on its own. i then stoped, shut the truck off, checked things liek my gas cap, looked around for anything loose, or anything leaking, nothing. (oil pressure and temp were normal). i then started it back up and it seemed to drive normal but still had the light on. went to the nearby nissan dealership but the service dept was closed but the sales guy said his pathfinder runs really bad when he puts arco fuel in it, and sure enough when i filled up i filled up with acro the day before, so i went and put some midgrade chevron in it. meanwhile the truck seems to be accelerating off the line good but getting bad milleage. i read in an earlier post how to check the code yourself, and did. it took me a while to count the flashes right. it seemed like it was flashing at differnet intervals, but the one that finally seemed right was it flashed 1 time, then 7 times then 2 times. so i guess if this is right the code would be a 172. so i checked the code on some other website and got that a code of p0172 (if this is the correct way to check it) is FUEL TRIM, BANK 1 SYSTEM TOO RICH.

any suggestions?

should i just wait and go to the dealer monday? how would u fix a system that is too rich anyway? reset the ECU?

btw, KC XE 2wd, now big tow no offroad w/ 2800miles

bestatchess · 05-16-2004, 05:36 AM

Any adjustments would need to be done by the dealer.

You don't have any intake mods do you? There was another thread where somebody used an aftermarket intake with a smaller air pipe and also got a fuel rich code. I wonder where the "fuel rich" sensor is located. Is it detecting a high concentration of unburned fuel in the exhaust like maybe some lousy gas is going through with incomplete combustion?

AzTitan · 05-16-2004, 11:10 AM

no i dont have any intake mods. im hoping it might be something like lousy gas though because i did fill up at an ampm with arco fuel which the salesguy at the nissan dealership said makes his pathfinder run really bad. i guess ill probably just have to wait untill monday to take it to the service dept. ill be sure to post what they say.

AzTitan · 05-16-2004, 05:35 PM

ok, so today i took the truck to autozone to have them check the code because it is hard to count the flashes of the light correctly. turns out the code was P1730 NOT P0172. i counted the flashes wrong. the P1730 is a transmission code. i read in an earlier post of MCTITAN he had the same code when his transmission felt like it went into nuetral on the freeway and the problem was fixed by flushing the tranny (debris on some switch or something). a tranny code would explain why it seemed like the truck downshifted. well thats the latest update so far. taking it to the dealer tomorrow so we'll see what they have to say.

bighawaii · 05-16-2004, 11:16 PM

glad to hear you probably only need a sensor and caught the problem before you were injured.

bighawaii · 05-16-2004, 11:27 PM

Quote:

Originally Posted by bestatchess

Any adjustments would need to be done by the dealer.

You don't have any intake mods do you? There was another thread where somebody used an aftermarket intake with a smaller air pipe and also got a fuel rich code. I wonder where the "fuel rich" sensor is located. Is it detecting a high concentration of unburned fuel in the exhaust like maybe some lousy gas is going through with incomplete combustion?

on the side note, its one of your o2 sensors. you seem to have a good idea on how they work.

skyhammer · 05-17-2004, 09:51 AM

I had simlair problems with my tundra. I nearly ran it out of fuel, After I fueld it up the service engine light came on. The truck ran fine but I had dropped out 5 mpg. Turned out all of my o2 sensor burned out. I believe there were 6 ing the tundra. Toyota fixed it for nothing even though it was out of warranty. Good theing because it would have cost over $700 to fix. From then I always fueld up before the light came on. I don't know if was or coincidence or cause and effect, bur now I don't take chances on running low on fuel.

AzTitan · 05-17-2004, 07:57 PM

well yesterday i was going up to the store and the truck would NOT shift out of 2nd gear. shut it off at the store, got back in, the AT CHECK light blinked a couple of times then went off and the truck shifted normally back home. in the mean time i have a spare car that i drove to work while the truck stayed at home. on the way home from work i stopped by the nissan dealer and told him about it, he said to just have it towed in. the service dpt is closed right now (too late) but the truck is being dropped off tonight.

This is a sad sight

, but hopefully it wont be too major.

Austin · 05-17-2004, 08:01 PM

Quote:

Originally Posted by bestatchess

You don't have any intake mods do you? There was another thread where somebody used an aftermarket intake with a smaller air pipe and also got a fuel rich code. I wonder where the "fuel rich" sensor is located. Is it detecting a high concentration of unburned fuel in the exhaust like maybe some lousy gas is going through with incomplete combustion?

"Too Lean" and "Too Rich" codes can easily happen when you do something as silly as change the pipe diameter of the MAF housing.

That's a big problem with cheap intakes - they have poor R/D and/or poor quality control. There is a high probability you'll muck up the MAF readings when using one.

The MAF (mass air flow) measures, obviously enough, the amount of air molecules flowing by it. It's a simple venturi with a temp sensor for temperature correction. When you change the size of the pipe it's sitting in, you change the characteristics of the measurement. Also, if you change the sensor mounting depth, you'll also change the characteristics of the measurement.

AzTitan · 05-18-2004, 10:23 PM

update: just got home from work (10:00 pm), message on the answer machine from the service guy said that they are going to order a new transmission

and that it is on back order so he expects it will be several days at least. these next few days are going to be hard without the BIG T.

bestatchess · 05-18-2004, 10:44 PM

Quote:

Originally Posted by AzTitan

update: just got home from work (10:00 pm), message on the answer machine from the service guy said that they are going to order a new transmission

and that it is on back order so he expects it will be several days at least. these next few days are going to be hard without the BIG T.

Did they tell you what they thought was wrong with the tranny?