I am still working on my drivability issues. I have walked away from the car for a week or two and am starting back on it. I replaced the air charge temp sensor that was on high limit range and cleared all codes. That seemed to help but could not get it to restart hot. I installed the "band-aid" spacer plate between the idle air bypass and that helped the rich hot restart problem. I intend to have the car retuned and remove the "band-aid" at a later date. Car seemed to run alot better. I let the car sit over night and at start up no problems. Drive down the block sputtering and hesitation. I have gone thru the checklist numerous times and performed all of the items listed. Now I decide to pull codes again and code 15?? EEC read only memory test failed?? What does this mean?? I want to fix this code before I move on to the KOER test to get an accurate test. Thanks
Contuined problems code 15??
- Thread starter sweet88gt
- Start date
SeventyMach1
Keep it lubed .... keep it straight .... and keep
http://forums.stangnet.com/showthread.php?t=549806
If that doesn't help .... do another search. Maybe you can find what you're looking for that way. Good luck with it man.
If that doesn't help .... do another search. Maybe you can find what you're looking for that way. Good luck with it man.
Ok, now I know what I am looking at can someone give me an idea how to troubleshoot such a problem?? I have a wiring diagram for my car and understand what Im looking at. I need to know if a simple voltage change will cause this code? Or am I looking for a complete loss of power??
I must be an idiot but still cannot do a forum search and find anything on code 15. Just a link to the old threads will give me a starting place. Thanks
I must be an idiot but still cannot do a forum search and find anything on code 15. Just a link to the old threads will give me a starting place. Thanks
For some folks, a ROM code can come from having the chip (why I asked).sweet88gt said:
I'd continue on with pulling KOER codes myself.
You might want to ohm out the ECT (for a hot start issue) but with a tune, etc, sometimes the fixes arent intuitive because we dont know what new parameters were set with the chip.
Good luck.
It is strange because I have pulled codes with the chip and never encountered this until today. Ill try running a KOER test and see what happens.
ECT sensor has been ohmed and in good working order. The IAT sensor was on the high limit of 15% out of range, meaning it was reading at the high side of normal operation. I replaced that sensor and double checked its ohm reading with the ECT and both ohmed the same value. They both work in the same ranges for ohm so I will take it that the ECT is working properly. I have check both sensors at cold and hot temps.Thanks
ECT sensor has been ohmed and in good working order. The IAT sensor was on the high limit of 15% out of range, meaning it was reading at the high side of normal operation. I replaced that sensor and double checked its ohm reading with the ECT and both ohmed the same value. They both work in the same ranges for ohm so I will take it that the ECT is working properly. I have check both sensors at cold and hot temps.Thanks
Code 15 - No Keep Alive Memory power to PCM pin 1 or bad PCM (Memory Test
Failure). The voltage to the Keep Alive Memory (KAM) is missing (wiring problem)
or the KAM is bad. The KAM holds all of the settings that the computer "learns" as
it operates and all the stored error codes that are generated as a result of
something malfunctioning while the engine is running. Use a voltmeter to check
the voltage to the pin 1 on the computer - you should always have 12 volts. No
constant 12 volts = bad wiring. If you do always have the 12 volts, then the KAM is
bad and the computer is faulty.
b]Note that some aftermarket chips will cause code 15 to set. Remove the chip,
clear the codes and retest.[/b]
Before replacing the computer, remove the battery ground cable for about 20
minutes. This will clear all the codes. Retest after several days of running. If the 15
code is gone, then don't worry about it. If it is still there, then you get to do some
troubleshooting.
Wiring diagrams for the proper model years are next…
For 86 models see http://www.autozone.com/images/cds/gif/large/0900823d80167158.gif
For 87 models see http://www.autozone.com/images/cds/gif/large/0900823d8016715e.gif
For 88 models see http://www.autozone.com/images/cds/gif/large/0900823d80167162.gif
For 89-90 models see http://www.autozone.com/images/cds/gif/large/0900823d8019595f.gif
For 91-93 models see http://www.autozone.com/images/cds/gif/large/0900823d80195960.gif
Ditch the chip. clear the codes and recheck in a week. If you still have a code 15,
either the computer's KAPWR (pin 1) is losing power when the ignition switch is off
or your computer is bad.
See the following website for some help from Tmoss (diagram designer) & Stang&2
Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/
Diagram courtesy of Tmoss & Stang&2birds
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
Failure). The voltage to the Keep Alive Memory (KAM) is missing (wiring problem)
or the KAM is bad. The KAM holds all of the settings that the computer "learns" as
it operates and all the stored error codes that are generated as a result of
something malfunctioning while the engine is running. Use a voltmeter to check
the voltage to the pin 1 on the computer - you should always have 12 volts. No
constant 12 volts = bad wiring. If you do always have the 12 volts, then the KAM is
bad and the computer is faulty.
b]Note that some aftermarket chips will cause code 15 to set. Remove the chip,
clear the codes and retest.[/b]
Before replacing the computer, remove the battery ground cable for about 20
minutes. This will clear all the codes. Retest after several days of running. If the 15
code is gone, then don't worry about it. If it is still there, then you get to do some
troubleshooting.
Wiring diagrams for the proper model years are next…
For 86 models see http://www.autozone.com/images/cds/gif/large/0900823d80167158.gif
For 87 models see http://www.autozone.com/images/cds/gif/large/0900823d8016715e.gif
For 88 models see http://www.autozone.com/images/cds/gif/large/0900823d80167162.gif
For 89-90 models see http://www.autozone.com/images/cds/gif/large/0900823d8019595f.gif
For 91-93 models see http://www.autozone.com/images/cds/gif/large/0900823d80195960.gif
Ditch the chip. clear the codes and recheck in a week. If you still have a code 15,
either the computer's KAPWR (pin 1) is losing power when the ignition switch is off
or your computer is bad.
See the following website for some help from Tmoss (diagram designer) & Stang&2
Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/
Diagram courtesy of Tmoss & Stang&2birds
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
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Ok, troubleshoot code 15 problem. I have good power to the pin for the computer. I replaced computer with a known working form a friend. Still code 15 new computer with the chip still installed. I will try the computer later today without the chip and see if it will run. My question is if the code is gone and it in fact is the chip what do I do next?? I need some sort of custom tune to get this to run to its potential. Any ideas??
On a side not this car still bucks and runs like crap in warm cruise. I have researched alot about the surge and buck for months and have tested and checked wiring for potential issues. Would the read only memory code that I am getting cause the adaptive learning to be erased when the car is shut off. If so, I have no adaptive learning with the computer would this cause some surge and overall running like crap?? I have the books on feul injection and read up on the subject but need some reinforcement on the issues.Thanks
Ok, troubleshoot code 15 problem. I have good power to the pin for the computer. I replaced computer with a known working form a friend. Still code 15 new computer with the chip still installed. I will try the computer later today without the chip and see if it will run. My question is if the code is gone and it in fact is the chip what do I do next?? I need some sort of custom tune to get this to run to its potential. Any ideas??
On a side not this car still bucks and runs like crap in warm cruise. I have researched alot about the surge and buck for months and have tested and checked wiring for potential issues. Would the read only memory code that I am getting cause the adaptive learning to be erased when the car is shut off. If so, I have no adaptive learning with the computer would this cause some surge and overall running like crap?? I have the books on feul injection and read up on the subject but need some reinforcement on the issues.Thanks
The code 15 means that the KAM memory and fixed ROM tables failed the self test. The error condition was so bad that it was just short of not doing anything, including diagnostics. Without working memory and readable good data in the computer rom tables, you will have performance problems.
I pulled codes without the chip in KOEO only and no code 15. As I thought the chip is the offender on that. I started the car and it did run, but very rough. I only idled in the garage for a few min. and pulled codes again just to see if anything was different. No code 15. My question or thought is this driveability issue is a tune problem. What I mean is that it can be fixed or at least better with the proper tune. Could the chip be the problem, say a defective device. Do the chips when installed always throw the code 15 no matter what??
joel5.0
Member
FYI.....
Suggest to have the chip redone. This is the very first scalar that needs to be set to "0" when you're using an alternate like the Tweecer. Typical problem with OTS performance chips. My 2¢.
Suggest to have the chip redone. This is the very first scalar that needs to be set to "0" when you're using an alternate like the Tweecer. Typical problem with OTS performance chips. My 2¢.
After pulling the chip, there probably isn't any usefal data in the KAM. I would drive the car with a very light foot for 20-30 minutes and see how it runs at low power. If the idle smooths out and there are no other problems surface, drive the car in a manner that reflects daily use, but without full power bursts. Avoid the full power driving until you have a custom burned chip using data from a group of Dyno runs.
joel5.0 said:
I couldnt agree more. I just could not justify the cost (at the time) of a standalone type system. I know have a better idea of the fule injection system but dont know if I can commit to any type of self tuning at this time. I would like to learn more but fear the complex systems may burn me out and want to sell the car. I have checked into the tweecer and have access to a A/F meter with datalogging. I will think about this more and see where I can go from there.
As for the test drive I will have to do that in a couple of days and Ill get back with some new information. Thanks
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