CHECK ENGINE light question

[UtahVXer]

Yesterday my CHECK ENGINE light came on with code P1171 which means lean mixture while accelerating. At the time, I was in cruise control, not accelerating, but I was going up a steep hill. Today before I had a chance to disconnect the battery, the light went back out on its own. My question is whether these lights automatically reset themselves. I thought they had to be manually reset which would indicate that I may have a faulty lamp. Thanks in advance for any info.

[Ldub]

You can check the ce light by turning on the ignition (not starting the engine)
it should come on every time the key is turned on.
As for resetting itself, I've had it happen after a tank of sub-par gas & heard of others resetting after retightening the gas cap.

Hope it's minor. ;)

[alleycat]

Sounds to me like you might have blown intake manifold gasket. Had same experience. 250 bucks later from dealer it was okay again. I saw them check it and do it while I waited.

[UtahVXer]

Thanks for the comments. I have driven several more days now without coming on again, so I hope it is not the manifold gasket.

[nfpgasmask]

Yup, I drove my VX real low on gas, got the CE light, engine was chugging. Put in a fresh tank of premium, CE light went away and VX is happy.

Bart

[Cobrajet]

I was getting the P1171/P0137/P0157 combination codes a few weeks ago. I cleared the codes, but they kept coming back. I did a search here and came up with several possible causes -- intake manifold gaskets, O2 sensors, MAF sensor, EGR, fuel filter, gas cap, etc. I tried the simple stuff like tightening the gas cap (I knew it wasn't that since the errors occurred before AND after a fill-up), checking the EGR nut, and listening for whistling intake leaks. After a week of failed cures I arranged a dealer service call. They have been good to my VX and me.

Their fix - replace MAF (most likely culprit - oil from the K&N filter. Probably should have tried cleaning this out myself), clean EGR, throttle body and fuel injectors (at 101K probably overdue anyway.)

After a week the CEL has not returned, throttle response is greatly improved, and mileage... still sucks!

The engine never ran bad. No rough idle. No stalling. So the TSB for intake gaskets didn't seem to apply here. The light always came on during moderate acceleration up a long, slight incline from a stop. I had done a few full-throttle passing maneuvers on flat roads without triggering codes. Normal acceleration on flat roads from a stop was OK, too.

Just wanted to add my experience for those searching for a solution to their CEL. Clean the MAF, EGR and throttle body.

[Pghachey]

Thanks for the info. Mine also came on yesterday driving in the rain on the way home from work. I checked the oil, and although it was a little low (between the fill & full lines) I didn't think that was the problem. I remembered I didn't change my PCV when I changed my oil a few weeks ago, so I went and bought a new one. My old one still rattled but I changed it anyways. I also cleaned my cone air filter and re-oiled it (thought maybe some moisture set off the warning light). While I did this, I disconnected the battery so I might reset the warning light if I could fix the problem. I also added a quart of Mobil-1 to top that off. I drove it last night after these cheap quick fixes and no "check engine" light so far today. I don't know if I fixed the problem for sure, but went the "easy" route first and maybe I'll be ok. Thanks for listening to my rambling. I'm not a mechanic, but my dad always told me to "try the simple things first" and sometimes they will take care of the problem. I'm keeping my fingers crossed. :)