"Service Engine Soon"

I have a 2000 Ford Mustang with around 163,000 miles on it. Tonight, the “Service Engine Soon” light came on. I have always heard horror stories about this particular thing and I was wondering if anyone had any theories about the possible things that can be wrong with my car.

I would appreciate hearing your ideas and how much the potential problems might run me. Due to the high mileage and a transmission that is going bad, I really don’t want to sink a lot more money into this car. So, am I screwed ?

Is this the “harbinger of doom” that everybody makes it out to be ?

No, the light isn’t a Dooms Day warning (That’ll probably arrive silently.). It’s just the engine computer telling you that “you have message”. It’s better to think of the light as an “early warning”. The cause can be minor. Go to Auto Zone auto parts store, or Pep Boys, etc. Let them read the trouble code. You can bring that trouble code here for comments and advice.

First there are two kinds of lights. Service reminders and repair alerts. Check your manual and find out if that light is trying to tell you it is due for an oil change or that there is a possible mechanic problem.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here. 

Regarding warning lights:

  1. if the coolant temp light comes on, shut off the engine ASAP

  2. if the oil warning light comes on, shut off the engine ASAP

  3. if a FLASHING MIL/CEL comes on, shut off the engine ASAP

    ASAP means driving to the berm of the highway right now and not waiting for the next exit.

But if the MIL/CEL is not flashing, then it’s not an urgent indicator.

Without information we are at a loss here too.

Please get the code(s) and post it back here so you can get prompt opinions. (Heh) Autozone and others will read the CEL for free. Just the code, not the translation.

I finally dropped by Autozone and got the code read today. The code was P0442: EVAP Emission small leak. Is this serious ? Is this going to be a costly repair ?

It could be just a hose. It may be tough to trace though. But I seriously doubt it’s going to cost a lot to fix.

Probably not expensive (once the leak is located).

The evap system contains a few components, so it will require a trace from the gas cap to the purge valve to begin with.

It may be a leak in the vent hose or canister (or not). A physical search has to be performed.

Could be just the gas cap isn’t sealing. Check the rubber seal on the gas cap. You might just replace the gas cap. No guaranty that it’s the cap.
Mechanically speaking, the car will continue to run with this P0442.

by any chance did you fill up the fuel tank just prior to the light?

open the gas tank cap, and rescrew it on tight. then drive the car for a couple of days, see if the light goes out. go to auto zone and have them reset the light (erase the code.)

if the check engine light comes back, then have the others ideas investigated.

Maybe the problem has gone away. On some cars you can check by disconnecting the battery for a few minutes so the error code will clear. Reconnect and see if the light comes on again. I think the dealer does this following a repair.

Check with Ford, there is a PCM flash availiable for this problem also. Do NOT go clearing the code without first checking things out and writing down any code(s).


I had a 96 Mustang with the 3.8 liter engine. It had the CEL code 1442 and it turned out to be the evap purge valve and also the evap sensor. I checked each and found them bad and replaced and didn’t have any more problems. I would first check the above before going this far. As stated earlier it could just be a bad or loose gas cap.

442 in my 97 was a rusted solenoid valve. The part cost me $36 at the dealer and assume this would be about $120 repair.