Contuined problems code 15??

sweet88gt · Aug 13, 2006

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

SeventyMach1 · Aug 13, 2006

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.

sweet88gt · Aug 13, 2006

Thanks, I did a search before posting a new thread but came up with nothing for just code 15.

HISSIN50 · Aug 13, 2006

Do you have a chip?

sweet88gt · Aug 13, 2006

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

sweet88gt · Aug 13, 2006

HISSIN50 said:
Do you have a chip?

Yes, A Diablo Sport chip with a tune for the blower.

HISSIN50 · Aug 13, 2006

sweet88gt said:
Yes, A Diablo Sport chip with a tune for the blower.

For some folks, a ROM code can come from having the chip (why I asked).

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.

sweet88gt · Aug 13, 2006

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

jrichker · Aug 13, 2006

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

sweet88gt · Aug 13, 2006

Ok, ditch the chip,clear codes, and rerun KOEO test. Simple enough. I just will not be able to drive the car. It will not run without the tune. Thanks

sweet88gt · Sep 10, 2006

back again

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

jrichker · Sep 10, 2006

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.

HISSIN50 · Sep 10, 2006

My limited understanding is that some chip burns are designed to remove some adaptive control. Otherwise the tune specs would wander.

sweet88gt · Sep 10, 2006

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 · Sep 10, 2006

FYI.....

CHECKSUM_BASE_ADDRESS - This is the starting address used to calculate a checksum on the ROM. The checksum test processes blocks of code until it reaches a base address that is 0. Set this value to 0 to remove KOEO error code 15 (checksum test error). The ROM checksum is valid only on the stock calibration—Once you change anything, the checksum is invalid and error code 15 is generated.

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¢.

jrichker · Sep 10, 2006

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.

sweet88gt · Sep 10, 2006

joel5.0 said:
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¢.

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

Contuined problems code 15??

sweet88gt

Member

SeventyMach1

Keep it lubed .... keep it straight .... and keep

sweet88gt

Member

HISSIN50

"How long does it take to get help in here?

sweet88gt

Member

sweet88gt

Member

HISSIN50

"How long does it take to get help in here?

sweet88gt

Member

jrichker

StangNet's favorite TOOL

Attachments

sweet88gt

Member

sweet88gt

Member

jrichker

StangNet's favorite TOOL

HISSIN50

"How long does it take to get help in here?

sweet88gt

Member

joel5.0

Member

jrichker

StangNet's favorite TOOL

sweet88gt

Member

Similar threads

Contuined problems code 15??

Member

Keep it lubed .... keep it straight .... and keep

Member

"How long does it take to get help in here?

Member

Member

"How long does it take to get help in here?

Member

StangNet's favorite TOOL

Attachments

Member

Member

StangNet's favorite TOOL

"How long does it take to get help in here?

Member

Member

StangNet's favorite TOOL

Member

Similar threads

Privacy & Transparency

Privacy & Transparency