Jeep Wrangler Forum banner

Ls swapping my 99 tj. need help with MIL light

5K views 8 replies 5 participants last post by  tfi racing 
#1 ·
I am in the process of ls swapping my 99 wrangler. I have the motor in and the wiring mostly wrapped up. I am trying to figure out how to tie into the factory harness. I would like to make the check engine light work with the ls motor. I believe its a printed circuit board. Any help would be greatly apprecited. Thanks
 
#2 ·
In looking at the '99 TJ wiring diagram. The warning lights in the dash which include the check engine light; are part of the CANBUS system. You won't be able to directly tie in to this system as their isn't a specific output wire to simply turn on the CEL. That said...how does the PCM for the LS engine output the CEL information? Is it with data lines as well or is does it have a dedicated wire specifically for the CEL? If it has specific output, rather than Data which communicates a multitude of data on two wires for different functions. You could in theory leave the bulb in place for the CEL in the TJs instrument cluster, pull the tabs away from the board and solder on a different connection which would be wired directly to the output from the LS PCM...this all makes sense in my head though I'm not sure how well I'm describing it.
 
#3 ·
Kinda right except for the CAN bus part

No XJ or TJ or ZJ or WJ used a CAN bus

Once OBD2 came along the 96-2001 XJ and the 97-2000TJ and the ZJ all used the twisted pair.CCD bus

Then the WJ and the 2001-2006 TJ used a single wire PCI bus

The goberment mandated CAN bus was on newer jeeps after the TJ and the WJ but it did show up in Durango with the 2004 redesign

Unfortunately your cluster instruments and CEL will only work if they get encoded bus info from like type Chrysler PCM and that ain't gonna work with a goberment motors engine


Sent from my iPod touch using Tapatalk
 
#4 ·
So i can or cannot make this work? i was thinking about tapping into the printed circuit board that is the gauge cluster and soldering the wire onto the existing MIL. then breaking the connection between factory MIL and the circuit board. Has anyone attempted this before? This job is for a customer that wants to use factory gauges. Thanks
 
#5 ·
Factory gauges do not take input from sensors they display CCD bus coded info from PCM so while you might rig a CEL no way to rig the gauges and could only rig the CEL if the goberment motors ECM Sends a illumination signal on a single wire and it probably also controls its CEL via its own bus encoded info - if so your plan will not even work for that


Sent from my iPod touch using Tapatalk
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top