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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

service engine soon light on

  • Thread starter Thread starter eric428
  • Start date Start date Apr 3, 2010
E

eric428

New Member
Jul 11, 2009
5
0
0
Apr 3, 2010
#1
  • Apr 3, 2010
  • #1
hello i am a newbie and just installed a o/r h-pipe and mil eliminator
and after about 15 minutes the service engine soon light came on
should i be worried? drove car for about an hour and it ran teriffic
any help would be great
thanks
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Apr 3, 2010
#2
  • Apr 3, 2010
  • #2
There are thousands of DTC codes. Go to the autoparts store and have the codes read. Post the full codes for us to see.
 
E

eric428

New Member
Jul 11, 2009
5
0
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Apr 3, 2010
#3
  • Apr 3, 2010
  • #3
ok will do thanks for the help
 
J

JerseyTrueBlue

Member
Feb 10, 2009
56
1
6
New Jersey
Apr 4, 2010
#4
  • Apr 4, 2010
  • #4
No need to worry man, they are called dummy lights for a reason. Unless you feel something wrong with the car just ignore it, or if you are tired of staring at it get over to autozone or another place that does the free scans and find out what code it's throwing. Bring the code back here and I'm sure someone would help you.
 

bradfier

Member
Mar 2, 2010
142
0
16
Apr 4, 2010
#5
  • Apr 4, 2010
  • #5
I’m not sure what the mil eliminator is but recently I installed MAC long tube headers and an O/R H-pipe. The problem might be with the O2 sensors as it is with mine. The car is designed to be run with cat’s and once the front O2 sensor reads the gases, they pass through the cat’s and is read by the rear O2’s the computer can make adjustments with air / fuel to make the car run correctly and pass emissions tests. Now that the cat’s have been removed rear O2’s read the same ratio as the front (or not at all) and tells the computer something is wrong. Typically this doesn’t change much of anything though you might notice a decrease in gas mileage. To fix it you can try O2 trickers or a tune. Handheld tuners can override the computer errors or if you have someone dyno tune it they should be able to do the same. If this is not correct let me know, but it is to the best of my knowledge.
 

patman0911

Founding Member
Jun 5, 2002
2,287
0
46
Tuscaloosa, AL
Apr 5, 2010
#6
  • Apr 5, 2010
  • #6
bradfier said:
I’m not sure what the mil eliminator is...
Click to expand...

MIL eliminators are designed to modify the voltage from the rear O2 sensors to mimic the readings the computer expects to see from a system with functioning cats - you must know them as O2 trickers.



I'm not sure one 15 minute drive is enough to trigger a "cat below efficiency threshold" code - I think it needs several complete drive cycles for that but I may be wrong.

If the MIL elims are faulty, installed incorrectly, or if the O2 sensor wiring or harness was damaged during the installation of the H-pipe then you may be getting a code related to that.

Or, it could be a coincidence and totally unrelated. Seems unlikely though.

Either way, you need to get the codes scanned to figure out what's going on. Don't ignore it for too long - you may not notice a change in drive-ability, but there may still be something doing long term damage to the motor, or something that's cheap and easy to fix now, but won't be in the future. If it is related to the rear O2 sensors, then it shouldn't affect much of anything (other than ability to pass a OBDII scan test), but if something else pops up, you won't know because the light is already on.
 

Night Shifter

Well-Known Member
Dec 24, 2005
1,710
27
59
Daytona
Apr 5, 2010
#7
  • Apr 5, 2010
  • #7
ive known some MIL eliminators that didnt keep the light off...
 
E

eric428

New Member
Jul 11, 2009
5
0
0
Apr 8, 2010
#8
  • Apr 8, 2010
  • #8
was finally able to get car scanned today
it came up as a p0161,po156
 

patman0911

Founding Member
Jun 5, 2002
2,287
0
46
Tuscaloosa, AL
Apr 8, 2010
#9
  • Apr 8, 2010
  • #9
P0156 02 Sensor Circuit Malfunction (Bank 2 Sensor 2)
P0161 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

You've got a bad connection, faulty MIL or damaged wiring on the driver-side rear 02 sensor.
 
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