Check Engine Light

84LX89GT · 02-17-2006, 02:19 AM

sorry sicy i don't browse as often as i used to, even though it seems like i'm the one making all the posts now and no one else is here. It's good to know there's at least one other person who peruses this message board

Anyway, there are a ton of reasons for a check engine light to come on with out any symptoms especially for an OBD-II car like yours ('96+ mustangs).
First before you bring it in, check and make sure your gas cap is tight - having it loose will cause an evaporative emissions code and send the check engine light.
OBD-II is an emissions based fault sender and the Processor (powertrain control module) will attempt to adapt to make it run right, so even with a fairly decent fault your car will run alright, which masks some of the problems it may have.
My best guesses are that the DPFE sensor could be bad (Delta Pressure Feedback exhaust sensor), there is an evaporative emissions fault, or maybe there is a vacuum leak causing Oxygen sensor or lean codes to be sent.
Those are the most common things i saw working as a technician at a ford dealership, but it's hard to guess without knowing the codes or what the PCM is seeing.
Best of luck, i hope this helped somewhat

02-17-2006, 02:19 AM	#1
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	Re: Check Engine Light sorry sicy i don't browse as often as i used to, even though it seems like i'm the one making all the posts now and no one else is here. It's good to know there's at least one other person who peruses this message board Anyway, there are a ton of reasons for a check engine light to come on with out any symptoms especially for an OBD-II car like yours ('96+ mustangs). First before you bring it in, check and make sure your gas cap is tight - having it loose will cause an evaporative emissions code and send the check engine light. OBD-II is an emissions based fault sender and the Processor (powertrain control module) will attempt to adapt to make it run right, so even with a fairly decent fault your car will run alright, which masks some of the problems it may have. My best guesses are that the DPFE sensor could be bad (Delta Pressure Feedback exhaust sensor), there is an evaporative emissions fault, or maybe there is a vacuum leak causing Oxygen sensor or lean codes to be sent. Those are the most common things i saw working as a technician at a ford dealership, but it's hard to guess without knowing the codes or what the PCM is seeing. Best of luck, i hope this helped somewhat __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

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