What is causing my Service Engine Soon light to stay on?

Asked by Jan 02, 2014 at 07:17 AM about the 2002 Ford Mustang GT Convertible

Question type: Maintenance & Repair

Since owning the car, (April 2012), I've had a problem with the Service Engine
Soon light staying on. The diagnosis came back that the hot air sensor was faulty.
I've had it changed as well as a couple of coils that went bad. I bought a set of
headers, because of an exhaust leak, (headers were rotted) and still the light
stays on and says it's the hot air sensor.

8 Answers

216,595

Do you have the factory catalytic convertors on? The O2 sensors will throw a code if not.

1 out of 1 people think this is helpful.
465

Some systems require a 'reset' for the ecu. Most of the time disconnecting the battery for more than 10 minutes will do the trick. Some of the mustang forums suggest: 1) disconnect the battery for 15 minutes, 2) reconnect the battery and start the vehicle, 3) let idle until warm, 4) turn A/C on (if equipped) and idle for 5 minutes, 5) drive the vehicle for 10 miles. If that doesn't work have the dealer reset it. Depending on the year there are different reset methods. If it still stays on run the codes again.

8 out of 8 people think this is helpful.

I have duel catalytic converters. As for the reset, the battery has been disconnected a couple of times. When I go to the dealer they would want to change the hot air oxygen sensor, (That's what shows up on the computer), but that has already been changed.

465

If resetting the ECU has no effect, then Tom may be right. But if the O2 sensors have been replaced and it still codes then look for the obvious like a frayed/shorted wire or a bad connector. You say you had the headers replaced. Were they replaced with stock or aftermarket parts? Has anyone done a test for a shorted or broken wires?

2 out of 2 people think this is helpful.

The headers are after market, purchased a couple of months ago, but I've been having the service light problem since I had the car.

465

I really don't know what to tell you to do. Something is definately amiss. Usually if you fix the code and the problem persisits it is something in the wiring either broken (open circuit) or shorting to ground. I have heard of problems as strange as being in the dashboard itself. Either way it is going to take time and patience to narrow down what circuit is causing the problem. There is a cheap fix, and I shutter to even suggest it. Just remove the bulb.

2 out of 2 people think this is helpful.

Yeah I suggested that but my mechanic advised against it. However to me for the light to be always on is the same as it never being able to come on. Either way it is not telling me anything.

20

I HAVE a 1997 gt mustang and my engine light came on had the mechanic check the code and it was just the gas cap so I had to buy a new one and the light went off

2 out of 2 people think this is helpful.

Your Answer

Add photo

Related Questions

  • Service engine soon light. 6 answers

    My 03 mustang has been a problem since day one, after 1 month, the engine cooling sensor has been replaced treat has also been replaced along with the fan because it over heated on us. So after a ...

    2003 Ford Mustang Base

    -

    Maintenance & Repair

  • Service engine soon

    2013 mustang, the service engine light is staying on and the car is idling rough and the gas petal is not working, it goes right to the floor

    2013 Ford Mustang V6 Convertible

    -

    Maintenance & Repair

  • Overheating mustang 02 V6 2 answers

    I sat in my car for 20 minutes, while it was idling with Ac on, Ac started to feel warmish, service engine soon light came on, temp gage was close to the red. Turned it off immediately, waited 30 ...

    2002 Ford Mustang

    -

    Maintenance & Repair

  • 2003 mustang with 2 problems. First, service light came on with code P1265-cylinder heads over temperature. second code, C1165 - Right rear speed sensor malfunction. 4 answers

    When looked up, says cylinder #5 high to low. What does it mean? How can it be fixed without going to dealer? Is it expensive? MOM, bought car for my son a college student, need help!!!. Has a ...

    2003 Ford Mustang Base

    -

    Maintenance & Repair

  • what would cause the check engine light to stay on? 3 answers

    The check engine light stays on all the time, the engine runs great, car drives great out on the road. The check engine light stays on all the time. The oil and fluids are all OK

    1992 Ford Thunderbird

    -

    Maintenance & Repair

Mustang

Looking for a Used Mustang in your area?

CarGurus has 41,215 nationwide Mustang listings starting at $1,699.

ZIP:

Search Ford Mustang Questions

UK Questions

Are you a UK consumer? CarGurus now has a discussion forum in the UK.

Ford Mustang Experts

#1 Tom Demyan
Tom Demyan
Reputation 3,980
#2 FordNut
FordNut
Reputation 1,230
#3 COMETGUY61
COMETGUY61
Reputation 990
View All

Related Models For Sale

Used Chevrolet Camaro
475 Great Deals out of 39,922 listings starting at $3,499
Used Chevrolet Corvette
292 Great Deals out of 20,420 listings starting at $3,688
Used Ford Mustang SVT Cobra
271 listings starting at $3,995
Used Ford F-150
3,210 Great Deals out of 205,087 listings starting at $1,779
Used BMW 3 Series
1,531 Great Deals out of 39,676 listings starting at $1,495
Used Jeep Wrangler
490 Great Deals out of 17,960 listings starting at $2,950
Used Chevrolet Silverado 1500
2,743 Great Deals out of 149,176 listings starting at $1,500
Used Nissan 350Z
80 Great Deals out of 1,506 listings starting at $3,490
Used Honda Accord
1,081 Great Deals out of 76,804 listings starting at $1,395

Used Cars For Sale

2014 Ford Mustang GT Convertible For Sale
73 listings starting at $21,500
2013 Ford Mustang GT Convertible For Sale
41 listings starting at $17,950