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Unread 07-07-2014, 09:34 AM   #1
esu
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ECU questions

Gents, have a few replacing an ECU questions.
1. There appear to be two sets of numbers, mine is 56028026 which is what most seem to be advertised by, however there is a 2nd set BFF300KYX1 which doesnt seem to jive with the 2nd set on any I have seen advertised. Must that be a match also?
2. I have seen ECUs advertised as "with security" and "without security", I have an idea but not sure what it means. I have keyless entry, is that the security they are talking about?
3. Is the ECU plug and play? Can I just swap 1 for another? Any programming involved?
Thx, Cory.

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Unread 07-07-2014, 01:13 PM   #2
Uniblurb
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The OE # is 5656028026 for your 95 4.0 and the other number is a SKU # which can usually be ignored. With or without security is referring to an alarm system and you have to match the ECU to which ever one you have. Some ECU units are pre-programmed while some aren't. Get one that's pre-programmed if possible. Stay away from the Florida/Miami reman units and Cardone1 has pretty reman units although it may be pricey. Shop around doing a search for the best deals and ebay even sells some used ones but not sure about their reliability. Some go to the jy but again you aren't sure what you're getting. Good luck!
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96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 93 4.0 XJ (spare), 96 4.0 XJ (son's)

-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
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Unread 07-07-2014, 02:35 PM   #3
esu
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Quote:
Originally Posted by Uniblurb View Post
The OE # is 5656028026 for your 95 4.0 and the other number is a SKU # which can usually be ignored. With or without security is referring to an alarm system and you have to match the ECU to which ever one you have. Some ECU units are pre-programmed while some aren't. Get one that's pre-programmed if possible. Stay away from the Florida/Miami reman units and Cardone1 has pretty reman units although it may be pricey. Shop around doing a search for the best deals and ebay even sells some used ones but not sure about their reliability. Some go to the jy but again you aren't sure what you're getting. Good luck!
Thank you for the info. I never even checked to see if I had an alarm, will have to look tonite.
Pre-programming refers to what exactly?
If i get a jy model are they just remove and replace providing the numbers match?
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Unread 07-07-2014, 04:16 PM   #4
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Ok, tried to figure out if I have a security system, I locked the jeep up with a window open, then reached in and undid the lock and opened the door which on most of my other cars would start the alarm going but nothing happened. Am I doing this right? Is there another fool proof way to check to see?
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Unread 07-07-2014, 05:26 PM   #5
Uniblurb
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Quote:
Originally Posted by esu View Post
Ok, tried to figure out if I have a security system, I locked the jeep up with a window open, then reached in and undid the lock and opened the door which on most of my other cars would start the alarm going but nothing happened. Am I doing this right? Is there another fool proof way to check to see?
That is the correct way to tell if you have an alarm/security system. There should also be a red light on the dash which will blink if the alarm system is activated. Some may abort the alarm system if it's malfunctioning but wouldn't think they'd go to the trouble of removing the small light on the dash too.


Quote:
Originally Posted by esu View Post
Thank you for the info. I never even checked to see if I had an alarm, will have to look tonite.
Pre-programming refers to what exactly?
If i get a jy model are they just remove and replace providing the numbers match?
Pre-programming means they would program the ECM at the re-manufacturing plant prior to selling. If you bought a reman unit which wasn't programmed you'd have to take it to the dealer to program to your VIN which would be about $100.

I noticed in your profile you have a 95 4.0 Limited. With all the electronic options which come with a limited you'd probably have to find the same year/model at the jy in addition to with or without 4WD.

Before we go any further; how do you know your ECM is bad and what's it doing?
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96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 93 4.0 XJ (spare), 96 4.0 XJ (son's)

-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
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Unread 07-07-2014, 06:51 PM   #6
esu
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Quote:
Originally Posted by Uniblurb View Post
That is the correct way to tell if you have an alarm/security system. There should also be a red light on the dash which will blink if the alarm system is activated. Some may abort the alarm system if it's malfunctioning but wouldn't think they'd go to the trouble of removing the small light on the dash too.




Pre-programming means they would program the ECM at the re-manufacturing plant prior to selling. If you bought a reman unit which wasn't programmed you'd have to take it to the dealer to program to your VIN which would be about $100.

I noticed in your profile you have a 95 4.0 Limited. With all the electronic options which come with a limited you'd probably have to find the same year/model at the jy in addition to with or without 4WD.

Before we go any further; how do you know your ECM is bad and what's it doing?
My issue started last summer. All winter the ZJ runs fine, soon as warm weather shows up I develop a stalling issue. In particular only when in stop and go traffic. 90 deg I can run all day on the hiway 70mph, a/c on etc with no problems. Soon as I hit a traffic light or two, stop for gas etc it starts stalling. Let it cool for a few minutes starts right up. Car never overheats. I had a long thread on it last year. I did everything on ZeeJays list to no avail. Checked fuel press and its at 39-40 but drops slightly when it stalls to maybe 33 or so. Did plugs, cap, rotor, wires, coil, fuel filter, flushed rad, new thermostat etc. So I actually don't know its bad but right now Im grasping at straws. Have no idea what to do next. Appreciate any thoughts.
http://www.jeepforum.com/forum/f13/o...issue-1546394/
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Unread 07-07-2014, 08:32 PM   #7
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i would suspect the fuel system. sorry i dont know a lot about the earlier fuel pump/regulator. IIRC there's a couple of factors involved in the pressure... just throwing it out there for someone to explain.

it's XX psi at some time and XX psi at another time... ??
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Unread 07-07-2014, 08:44 PM   #8
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Quote:
Originally Posted by esu View Post
My issue started last summer. All winter the ZJ runs fine, soon as warm weather shows up I develop a stalling issue. In particular only when in stop and go traffic. 90 deg I can run all day on the hiway 70mph, a/c on etc with no problems. Soon as I hit a traffic light or two, stop for gas etc it starts stalling. Let it cool for a few minutes starts right up. Car never overheats. I had a long thread on it last year. I did everything on ZeeJays list to no avail. Checked fuel press and its at 39-40 but drops slightly when it stalls to maybe 33 or so. Did plugs, cap, rotor, wires, coil, fuel filter, flushed rad, new thermostat etc. So I actually don't know its bad but right now Im grasping at straws. Have no idea what to do next. Appreciate any thoughts.
http://www.jeepforum.com/forum/f13/o...issue-1546394/
I read through the whole thread and even made a post in it about engine ground locations. No mention of testing the crank sensor and try the resistance test between pins B&C in my signature. It may help if it's stalled when trying this or a no-start condition. I will say the last of the 4 crank sensors I installed it wanted to cough, sputter, die when at operating temps when stopped at idle. In other words the crank sensor failed once it got hot at idle. I shouldn't even count the middle 2 cranks sensors I installed because they were aftermarket and didn't work worth a hoot. Not saying this is your problem but definitely worth checking before going for a $300 ECM or pulling one at a jy. Good luck.
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96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 93 4.0 XJ (spare), 96 4.0 XJ (son's)

-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
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Unread 07-07-2014, 08:53 PM   #9
esu
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Quote:
Originally Posted by Uniblurb View Post
I read through the whole thread and even made a post in it about engine ground locations. No mention of testing the crank sensor and try the resistance test between pins B&C in my signature. It may help if it's stalled when trying this or a no-start condition. I will say the last of the 4 crank sensors I installed it wanted to cough, sputter, die when at operating temps when stopped at idle. In other words the crank sensor failed once it got hot at idle. I shouldn't even count the middle 2 cranks sensors I installed because they were aftermarket and didn't work worth a hoot. Not saying this is your problem but definitely worth checking before going for a $300 ECM or pulling one at a jy. Good luck.
The cps had died at one time, I replaced it with an aftermarket which died 1 day later causing me to get stuck twice in 2 days. I finally bought an OEM mopar cps which has been in for a year a working fine, I think. I can give the cps a test tomorrow night when I get home from work.

I actually have one of the aftermarket cps that I removed while it was still working in my trunk, I could put that back in and see how it runs?
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Unread 07-07-2014, 08:58 PM   #10
esu
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Quote:
Originally Posted by ZeeJay1997 View Post
i would suspect the fuel system. sorry i dont know a lot about the earlier fuel pump/regulator. IIRC there's a couple of factors involved in the pressure... just throwing it out there for someone to explain.

it's XX psi at some time and XX psi at another time... ??
I thought fuel originally also, now not sure. I cant explain the drop in psi but would a drop from 39 to 33 cause it to stall? My 82 vette runs at 15 psi just fine. Ive seen some posts here where fuel pumps were "overheating" and failing but if the dam thing is submerged in liquid how does it "overheat"? The regulator is integral to the pump in this year.
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Unread 07-07-2014, 08:59 PM   #11
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would a drop from 39 to 33 cause it to stall?
i did some googling around the forum on your behalf and saw where someone said 31 should be fine... IDK.
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Unread 07-07-2014, 09:02 PM   #12
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i did some googling around the forum on your behalf and saw where someone said 31 should be fine... IDK.
Thanks Zee, Ive seen some posts myself that say 39 plus or minus X percent, the thing is why did it drop?
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Unread 07-07-2014, 09:03 PM   #13
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is your regulator hooked to the vacuum?
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Unread 07-08-2014, 06:29 AM   #14
esu
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is your regulator hooked to the vacuum?
I have no idea, all I know is its mounted with the pump.
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Unread 07-08-2014, 09:59 AM   #15
esu
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Quote:
Originally Posted by Uniblurb View Post
I read through the whole thread and even made a post in it about engine ground locations. No mention of testing the crank sensor and try the resistance test between pins B&C in my signature. It may help if it's stalled when trying this or a no-start condition. I will say the last of the 4 crank sensors I installed it wanted to cough, sputter, die when at operating temps when stopped at idle. In other words the crank sensor failed once it got hot at idle. I shouldn't even count the middle 2 cranks sensors I installed because they were aftermarket and didn't work worth a hoot. Not saying this is your problem but definitely worth checking before going for a $300 ECM or pulling one at a jy. Good luck.
Hey, was reading one of your threads where you mention a spacer with the cps? I cant remember any spacer, paper or otherwise?? Necessary? Can they still be gotten?
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