How can I tell if my ECU is shot? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > How can I tell if my ECU is shot?

Engo winches available at www.rockridge4wd.com! Free shippOur 2014 DynoMax mail-in rebate March1- June 30th is here!OPTIC ARMOR WINDOWS all sale now !!!!!!!!

Reply
Unread 03-28-2010, 01:30 PM   #1
lexinator02
Registered User
1995 YJ Wrangler 
 
Join Date: Sep 2009
Location: waukesha, wi
Posts: 126
How can I tell if my ECU is shot? SHE STARTED!!!

I have a 90 yj with a 2.5L and a 5 speed and I am pretty sure my ECU is shot. Is there any ways I can use a mulitmeter to see if it is shot or do I just have to bite the bullet and buy a new one to see?

Dave

__________________
Low Output 4 Cylinder Jeep Club Member # 187
1995 YJ

Last edited by lexinator02; 03-31-2010 at 04:22 PM..
lexinator02 is offline   Reply With Quote
Unread 03-28-2010, 04:35 PM   #2
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 5,614
Quote:
Originally Posted by lexinator02 View Post
I have a 90 yj with a 2.5L and a 5 speed and I am pretty sure my ECU is shot. Is there any ways I can use a mulitmeter to see if it is shot or do I just have to bite the bullet and buy a new one to see?

Dave
When you turn your ignition to the ON (not START) position and your various dash gauges light, up does your CEL come on also? If it does it is probably OK.
__________________
"Once good behavior becomes the exception and not the rule your society has begun to fail…..we are there." laybackman

If your girl is throwing gang signs with her toes you're hitting the spot.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Unread 03-28-2010, 04:57 PM   #3
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 13,727
Its a 1990 so it predates the SMEC or the SBEC so the CEL light isnt a good indicator. I guess the better question is why do you think the Engine controller is bad? Whats wrong with your jeep?
Que89YJ is online now   Reply With Quote
Unread 03-28-2010, 06:20 PM   #4
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 5,614
Quote:
Originally Posted by Que89YJ View Post
Its a 1990 so it predates the SMEC or the SBEC so the CEL light isnt a good indicator. I guess the better question is why do you think the Engine controller is bad? Whats wrong with your jeep?
Since it was a 2.5 I thought it was since it has TB injection. But you are right that all started in '91 didn't it? But the good question is what you asked the OP..why do you think it needs to be replaced?
__________________
"Once good behavior becomes the exception and not the rule your society has begun to fail…..we are there." laybackman

If your girl is throwing gang signs with her toes you're hitting the spot.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Unread 03-29-2010, 06:03 AM   #5
lexinator02
Registered User
1995 YJ Wrangler 
 
Join Date: Sep 2009
Location: waukesha, wi
Posts: 126
http://www.jeepforum.com/forum/f12/a...st-lol-991642/

I have this thread going I just wanted an individual question about the ECU. I would love an answer like take a multimeter at all these plugs on the ecu harness and you should get this value. That way I would know if the inputs and outputs are normal.

Dave
__________________
Low Output 4 Cylinder Jeep Club Member # 187
1995 YJ
lexinator02 is offline   Reply With Quote
Unread 03-29-2010, 11:13 AM   #6
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 5,614
Quote:
Originally Posted by lexinator02 View Post
http://www.jeepforum.com/forum/f12/a...st-lol-991642/

I have this thread going I just wanted an individual question about the ECU. I would love an answer like take a multimeter at all these plugs on the ecu harness and you should get this value. That way I would know if the inputs and outputs are normal.

Dave
You would need to know the electrical values of all the pinouts on the brain whether they be input OR out put voltages. A FSM is the best place for that information.
__________________
"Once good behavior becomes the exception and not the rule your society has begun to fail…..we are there." laybackman

If your girl is throwing gang signs with her toes you're hitting the spot.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Unread 03-29-2010, 11:21 AM   #7
lexinator02
Registered User
1995 YJ Wrangler 
 
Join Date: Sep 2009
Location: waukesha, wi
Posts: 126
well for the heck of it I decided to open up the ECU and check it out. I found a capacitor/resister completely burnt and cracked and the backside of the board was burnt in that spot as well so I think its safe to say my ECU is shot lol

Dave
__________________
Low Output 4 Cylinder Jeep Club Member # 187
1995 YJ
lexinator02 is offline   Reply With Quote
Unread 03-29-2010, 02:24 PM   #8
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 5,614
Quote:
Originally Posted by lexinator02 View Post
well for the heck of it I decided to open up the ECU and check it out. I found a capacitor/resister completely burnt and cracked and the backside of the board was burnt in that spot as well so I think its safe to say my ECU is shot lol

Dave
This link goes to one of several fixes for bad capacitors in a brain;
http://www.jeepforum.com/forum/f12/c...rs-ecu-492597/
__________________
"Once good behavior becomes the exception and not the rule your society has begun to fail…..we are there." laybackman

If your girl is throwing gang signs with her toes you're hitting the spot.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Unread 03-29-2010, 03:03 PM   #9
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 13,727
He has the renix controller on the Renix controller on the inside of the vehicle. Its the first time I heard of this happening. Pics would be appreciated. I agree though. It should be similar in the issues as the Sbec and it should be repairable. The cao should be on the input pin for power and should be easily replaced. A resistor would be a new one for me too.
Que89YJ is online now   Reply With Quote
Unread 03-29-2010, 03:13 PM   #10
lexinator02
Registered User
1995 YJ Wrangler 
 
Join Date: Sep 2009
Location: waukesha, wi
Posts: 126
Here are some pics of what I found. I could not tell if it was a resistor or capacitor...










Dave
__________________
Low Output 4 Cylinder Jeep Club Member # 187
1995 YJ
lexinator02 is offline   Reply With Quote
Unread 03-29-2010, 03:39 PM   #11
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 5,614
Quote:
Originally Posted by lexinator02 View Post
Here are some pics of what I found. I could not tell if it was a resistor or capacitor...










Dave
I think it is a big resistor. What you need to know is what was it's value. Can you see the stripes on it? That gives you the value.

Resistor Color Code Table And Calculator
__________________
"Once good behavior becomes the exception and not the rule your society has begun to fail…..we are there." laybackman

If your girl is throwing gang signs with her toes you're hitting the spot.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Unread 03-29-2010, 04:15 PM   #12
lexinator02
Registered User
1995 YJ Wrangler 
 
Join Date: Sep 2009
Location: waukesha, wi
Posts: 126
no its solid black from being burnt. It does look a lot like the resistor in the 2nd pic though...
__________________
Low Output 4 Cylinder Jeep Club Member # 187
1995 YJ
lexinator02 is offline   Reply With Quote
Unread 03-29-2010, 04:26 PM   #13
wrangler76
Registered User
1995 YJ Wrangler 
 
Join Date: Sep 2009
Location: Carson, WA
Posts: 414
Does the "R125" on the board specify anything useful?
wrangler76 is offline   Reply With Quote
Unread 03-29-2010, 04:32 PM   #14
JOExFROMxNY
Registered User
1988 YJ Wrangler 
 
Join Date: Dec 2009
Location: Long Island, NY
Posts: 744
Quote:
Originally Posted by wrangler76 View Post
Does the "R125" on the board specify anything useful?
R=resistor
D=diode
C=capacitor

Look for a number underneath it. That "R" might be for the resistor next to it.
JOExFROMxNY is offline   Reply With Quote
Unread 03-29-2010, 04:33 PM   #15
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 5,614
Quote:
Originally Posted by lexinator02 View Post
no its solid black from being burnt. It does look a lot like the resistor in the 2nd pic though...
That was my thought also it does look quite similar. I wouuld look inder the burntt one also and see if you can see any hint of the stripe(s) on it OR find one that is the same size and see what it's value is. Then buy one and swap out the bad one for the new one....What have you got to lose at this point?
__________________
"Once good behavior becomes the exception and not the rule your society has begun to fail…..we are there." laybackman

If your girl is throwing gang signs with her toes you're hitting the spot.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.