Hello guys have a 2000 Grand Cherokee Dtc P1388. Keeps blowing fuse #26 I power dist box. Cut wire at ecm at C3 pin 12 dg/lg. Fuse does not blow any more. At this point I condemned ecm. Installed another ecm reconnected wire at pin 12 new fuse and it blew again as soon I turned ign switch to on position. Removed wire at pin 12 new fuse turned on ign switch fuse ok. At this point thought I had a bad ecm, point to be considered these ecm's are from a bone yard. I thought I had a defective ecm got another and same thing happens. Now starting to get agitated. Tried these ecms including original which are 3 ecms in total on another vehicle and fuse #26 does not blow. From this good running vehicle tried ecm to troubled vehicle and fuse #26 blows. Doing same testing procedures getting same results. There are lots of blown fuses around and cannot figure out why this is happening. Even bypassed asd relay with jumper wire on terminals #87 to #30 on power dist box eliminating coil side of asd relay circuit and same thing happens. I even created an open in C102 pin #4 which shares power from fuse #26 and still have same issue. I'm lost at this point please help. Never ran into a situation like this and have been doing electrical repairs for some time now. Need help!

 

What circuit does that fuse protect? The ECM probably isn't the problem, the problem is somewhere in the wire harness.

 

It protects the ecm

 

According to this, fuse 26 is for the injectors; Also, my book says a code P1388 shows an open or short in the ASD relay circuit.

 

Yes thank you. That is true. Have eliminated everything related to that fuse even bypassed asd relay by jumping 87/30 which eliminated coil circuit on asd relay. I cut wire at ecm coming from fuse 26 and short goes away. Eliminating harness, injectors, coil rail and asd relay. Put vehicle in original state with wire cut at ecm no short connect wire back short again. Running out of hair yo pull out of my head. Hate to see this go to junk yard. But made by man should be able to be fixed by man.