computer burned up ?? with pic -
LinkBack Thread Tools
post #1 of 4 Old 06-10-2013, 09:45 AM Thread Starter
Registered User
2002 KJ Liberty 
Join Date: Oct 2012
Location: crousetown
Posts: 18
computer burned up ?? with pic

ok was having some problems few mths ago here is link

now just getting time to work on this again .it all started with one coil not getting power then 2,3,4 ect,tried a new computer and it worked on same 5 cylinders as when the problem started .so today i decided to take the old computer apart and this is what i find

Attached Thumbnails
xxtegra is offline  
Sponsored Links
post #2 of 4 Old 06-10-2013, 09:47 AM Thread Starter
Registered User
2002 KJ Liberty 
Join Date: Oct 2012
Location: crousetown
Posts: 18
what would cause this ? cut wires in the harness?
xxtegra is offline  
post #3 of 4 Old 06-11-2013, 07:00 AM
Registered User
2002 KJ Liberty 
Join Date: Jul 2007
Location: White River in the Bush, South Africa
Posts: 1,426
Originally Posted by xxtegra View Post
what would cause this ? cut wires in the harness?

Yeah something shorting out to chassis somewhere probably.
I did see a link somewhere of a possible short somewhere near the alternator but cannot find the link now...the short could be anywhere and you need to trace it before frying another PCM.

It is possible you have a bad coil pack for instance which blows that part of the you swap that bad coil pack with one in a different position and the bad coil pack blows another section of the PCM and so on.

It can be difficult to physically trace wires fraying to ground as the harness tends to take a long round about will need to remove the battery, disconnect the PCM, measure all leads coming out of the PCM for continuity to ground using a good Multmeter.

You can get the circuit diagrams for your 2002 KJ here.....included in the 2002 KJ Service Manual.

There is no circuit diagram for the PCM itself but if you physically trace the blown components in the PCM to nearby PCM connector pins you can check where those connector pins go to in the circuit diagram Connector Pin-out Table....should narrow down your path to take ie. coil pack, injector etc.

Note that as stated before in your link, the coil packs all get +12 volts on one side while the other sides are grounded in turn by the PCM so if one of those leads goes to ground intermittantly the coil pack could burn out which in turn could cause that circuit to draw too much power and burn out the relevant Transistor/SCR in the PCM.

2002 2.5 Export CRD Manual 5 speed.
Billwill is offline  
post #4 of 4 Old 06-11-2013, 07:58 AM
Registered User
2005 KJ Liberty 
Join Date: Jul 2011
Location: Castle Pines
Posts: 3,296
Just a word of correction, the V6 has coil on plug, not coil packs, different systems. Regardless, you have battery power on one side of the coil connector, and a pcm controlled ground on the other. With multiple transistors cooked, you have a problem that needs fixed before you put another pcm in. Make sure you check the powers and grounds to the pcm, and also check for shorts to ground in the wiring to the ignition coils from the pcm. Follow thru what Billwill said, as that is a sound starting point. If you have the old ignition coils, check their resistance on the primary side, the two pins where the connector plugs into, then also one pin at a time against the secondary side of the coil...where the spark comes out.
streetglideok is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome