Strange "Service Engine Soon" light-why?

StevX · Sep 23, 2009, 02:17 PM

08 GSR
21,000 miles
No mods, besides a conservative Ecutek tune done about 13 months ago
No track use, 0 launches, no autocross use

I was pulling out of a parking lot today and slowly driving towards the street in first gear. RPMs rose to about 5 grand under light throttle and then fell as I approached the red-light intersection to the street. As I pulled out into the street and began accelerating in first gear (again light throttle), the car pulled back (the car would not accelerate) and the "Service Engine Soon" light came on. I immediately pulled into a gas station, and turned the car off. Waited a few minutes, turned the car on and the service engine soon light is still lit. The car seems to drive fine, although I have stayed out of boost. The temp gauge appeared normal. Any ideas?

I'm leary of taking the car to a dealer due to the tune.

**atombomb33** · Sep 23, 2009, 02:32 PM

Could be a number of things. Try to find your local AutoZone and have them pull the code. Then post that up and we can help better

Drew84 · Sep 23, 2009, 02:39 PM

Flux Capacitor failed. See it all the time.

mlomker · Sep 23, 2009, 03:24 PM

Quote:

Originally Posted by StevX

I'm leary of taking the car to a dealer due to the tune.

Pull the code or disconnect the negative battery cable for a while to get rid of the CEL. If it were something serious then it'll come back on again.

StevX · Sep 23, 2009, 03:53 PM

Had the code pulled at autozone. It's P1238 - "Manufacturer control fuel air metering" is what came up on the scanner.

When turned the car back on after getting the scan, the Service Engine Soon light was gone and the car seemed to drive normal on the way home.

Thoughts?

raytrix · Sep 23, 2009, 04:26 PM

Narrowband messed up? Or cat going out?

JJsEvo8 · Sep 23, 2009, 04:43 PM

Try cleaning your MAF sensor (there is a spray for this) and check your air filter.

blk-majik · Sep 23, 2009, 05:21 PM

In EVO world, P1238 = Mass airflow sensor plausibility (torque monitor). I'm not sure how that differs from P1235, but P1235 (also MAF plausibility) can be cause by overboosting or a bad MAF. Tunes that increase boost can trigger it at peak boost (around 3500rpm).

StevX · Sep 23, 2009, 07:53 PM

Hmm... peak boost was not raised in my Ecutek tune, and I replaced the air filter less than 3000 miles ago. Perhaps a dirty MAF Sensor?

If I end up taking it to the dealer, will the aftermarket tune be blatantly obvious when they try to pull the code, or is that something they would discover only if they were looking for it?

mlomker · Sep 23, 2009, 08:25 PM

Quote:

Originally Posted by StevX

is that something they would discover only if they were looking for it?

Yup, and some dealers look for it. Nothing is for certain if you modify the car...that's just how it is.

That being said, you'd be better off having your own Tactrix cable/laptop so that you can change your flash when you need to. A quick search on your error code on here brought up some interesting threads...one of them bashed mail-in tunes as being inadequate...I'd talk to your tuner.

buchnerj · Sep 23, 2009, 08:45 PM

Quote:

Originally Posted by Drew84

Flux Capacitor failed. See it all the time.

Avoid the dealership at all times. Go to the local parts store and DIY at all costs. Most dealerships will find something that can void your warranty the second they pop your hood. Clean the MAF sensor and see if it comes back, if you cleared it and it didn't come back after a couple starts and little drives you should be fine, could have been a piece of debris that made it through the filter that fouled it up. Mine used to come on when i was under WOT, cleaned it with the CRC spray, no problem anymore... my 2c

Brokenevo · Sep 23, 2009, 09:27 PM

just go to service its under warranty

StevX · Sep 23, 2009, 10:10 PM

Thanks for the replies.

Another thread claimed the code is a result of high partial throttle boost (which seems to fit my circumstances).

FWIW, my tune was not a mail-in tune.

So in other words, unless the dealer was looking for a tune they would not notice it?

Brokenevo · Sep 23, 2009, 10:24 PM

you are correct, my good buddy is a diamond tech for mitsu, they wont know it was ecu tuned unless they really look into it. I just asked him this question too earlier. I guess TTP in Florida is locking the ECU's back up after they tune them too.

evo_RS · Nov 1, 2009, 11:41 PM

Hi guys, i have the same problem, today I install the injen UICP, injen intake pipe and the Gredddy EBC, i start the engine after i hook up everything and the Service Soon Light came out, what could be the problem?
I clean the MAF with a CRC contact cleaner from the inside because was dirty, did i mess up the MAF with the conctact cleaner? i did that before and didn't have any issues.

Can someone help me

Mod are:
Nesei LICP
Still have the stock ECU without a flash
Apexi Intake

thanks