drew6775

I need some help here I got a 99 xj with 4.0 and aw4 I've been fighting this electrical problem for a few days now and finally figured what part of the problem is. I haven't been able to start my poor xj it just cranks but doesn't turn over also my gas gauge and voltage gauge don't work and fuel pump is always on. I replaced my CPS but it didn't work. I then cleaned my grounds sense they were caked with oil from the old valve cover gasket that didn't do anything but it probably didn't hurt. I then replaced my relay sense one was clicking and buzzing ASD. I checked my fuses by hand and they looked fine but I was convinced that it had to be a blown fuse so i checked it with a fuse tester and sure enough number 10, Auto Shutdown Engine Controller and 11, Auto shutdown,Oxygen sensor was not lighting up so i put 2 new ones in and as soon as i turned the key they blew again. I want to know where the short or bad sensor or something is causing this PLEASE HELP, Thanks

CCKen

Have you ever had water leak in to the passenger foot well?


Have you driven your Jeep in to deep water where the water was up to the dash?


There is a possibility that your Junction Block (passenger foot well fuse panel) is corroded.


If you want, pull the panel off the JB and remove connector C4 (see pic) and some other connectors, and look for green corrosion.


99 JB:





JB Access:





JB Removal - If Required:





Corroded JB:











.

drew6775

Thank you for the reply, I will defiantly check into that it rained really heavy for a few days so that might be it but why would it blow in the distribution center under the hood if it is that? I have the check engine light on and the no bus sadly I don't have a code scanner and I don't have money for a tow to get it scanned I'm only 17 and I don't got a lot of money. I drove it just a few days before all this happened and the rain and it drove awesome since I did a tune up and a bunch of other things before it did this it's really giving me a headache!!!

CCKen

Actually, that Junction Block is inside the Jeep, in the passenger footwell.


If the problem just cropped up after it rained, and drove awesome, then I think it may be another issue. A "No Bus" is telling you there is a communication issue with the CCD Bus. It takes several things to trigger that.


The rain may have gotten some critical engine sensors shorted out. Pull the connectors off each sensor and connector sets in the engine bay (not the PCM at this time) and blow them out using CRC QD Electronic Cleaner (auto parts stores), and inspect them for water intrusion.


Pull the cover off the Power Distribution Center (PDC) in the engine bay and see if water got in there.

drew6775

Thank you for the help, my xj did that at my grandpa's so I've been having to run back and forth from there. I'm defiantly gonna do those two things you told me to do when I go over there again. I know were the JB is the fuses I'm blowing are in the PDC and the PDC is not wet luckily. I also replaced the ASD relay and the cooling fan relay since it messed with those to. I also peeled those plastic sleeves around all the wires and looked at the wires and they weren't nicked or melted so I'm hoping it is around the connectors. There any connector I shouldn't pull and clean?

freegdr

picture of exact fuses its blowing will help.

CCKen

Here's a '99 PDC layout and a pic showing some fuses.

Which fuses are blowing? F10 & F11?


F10 powers the Starter.,


F11 powers the Junction Block. Back to inspecting the JB wouldn't you say....

CCKen

If the Starter and JB fuses are blowing you may want to pull the PDC apart and see if those fuse wires are shorting out some how.

drew6775

Thanks you guys for your help, sorry for the confusion I apparently wasn't looking at the right thing. thank you for the diagram and picture that helps a lot! I'm blowing according to the diagram f24 15a O2's heaters and f21 20a fuel injectors/coil in the PDC. I'm not blowing any fuses in the JB the image I was looking at online and got 10 and 11 fuses was completely the wrong thing! I'm not sure if this has anything to do with what's going on but I fixed 2 wires in the door jam a little bit ago since the windows weren't working,could that have a short in there that I didn't see in the other wires and causing this?

CCKen

Remove the ASD relay and turn the key to start. See if F21 and/or F24 blows.


Both of those fuses are powered from the ASD relay when it is energized. The ASD relay will not energize unless the PCM sees an engine rotation signal from the CPS. The ASD relay control coil is powered from fuse F11 in the JB when the key is turned to START/RUN. When the PCM sees engine rotation it will provide a ground to the ASD relay control coil, pulling in the relay power contacts, which powers F21 and F24.


If F21 and F24 are being shorted to another power source inside of the PDC, like the fuel pump, it might be the culprit.


Disassemble the PDC so you can examine the wires inside the PDC.


Remember to remove the negative post connector from the battery before working on the PDC.

drew6775

Thanks they blew again with the negative battery terminal disconnected and the key off with the ASD Relay out. both of the fuses tested very weak on top of the fuse with a fuse tester. The f11 is fine and not blown in the JB. you want me to take the PDC off and look at the wires under the PDC now?

CCKen

This would be a good idea. Only completely disconnect the battery.


Edit: Take a good look at the battery cable from the battery to the starter.

drew6775

all right I'll do that thank you! I got to go get fuses to I ran out!

drew6775

I took the wire sleeve of all the battery cable wire all the way down to the starter and there is no bare wire except there is a splice that runs to the PDC touching the body and the plastic wore off the splice so its just the metal splice could that be it? If not I'll look at the PDC.

CCKen

Move that 'splice away from the body and see if it helps.


Do you have a camera that you take a pic of that splice that goes to the PDC.


Is this a separate wire from the starter cable?