Hello, I found this diagram with a Browser search for 1998 jeep pcm schematics. The site, JeepZ.com/forum had this article. It seems to show what you need. I hope my solution is helpful to you.
I understand you are looking for the schematic but it's going to be hard to located.
As your are waiting for the schematic,I recommend you to start checking for damage on the electrolytic capacitors inside the Power-train Control Module.
Here are few sample pictures of what your need to look for.
These are not the actual pictures of your TCM.
Look for sign of leaks on the base of these capacitors.
The leak will be on the circuit board.
Also look for top of the capacitor.
A failing and failed capacitor will be CONVEX outwaINTERNAL electronic schematic Powertrain Control - mustgo_27.jpg="/uploads/images/mustgo_27.jpg" alt="mustgo_27.jpg" class="h_mi" />
Replace these caps with the same micro f rating.
The voltage rating can be higher then the exiting cap.
I hope some expert can come though with the schematic but checking all capacitors for damage is a good start.
Please keep me up to date on the repair and upgrade via email.
TO confirm this you need to check the wirings :---
Power for the fuel pump is supplied by fuse #16 in the Power Distribution Center (PDC), goes through the Fuel Pump Relay and then to the Fuel Pump and the ground completes the circuit. Power for the Fuel Pump Relay coil is supplied by fuse #18 in the PDC and the Powertrain Control Module (PCM) supplies ground. It is a fairly simple circuit to check. The first thing to do is check all the fuses, especially #16 and #18. If you have they are good then you will need to pull the fuel pump relay and check for power, with the key ON at the dark green/black wire and orange wire. The DG/BK wire is the power for the fuel pump and the OR wire is the power for the relay coil. If you have power there connect a jumper between the DG/BK wire and the dark green/white wire. You should hear the fuel pump running. If not there is a problem in the DG/WT wire from the relay to the pump.
Okay, lets assume that checks out fine, the next thing to do is replace the fuel pump relay and ground the dark blue wire. You should hear the fuel pump running. Okay? Good, now go to the PCM located on the firewall in the engine room. It has three large connectors, black, white and grey. There is a DB wire in cavity 19of the grey connector. Ground this wire and you should hear the fuel pump running. If it does then the wiring for the fuel pump circuit is all good and the PCM will need to be replaced. If it doesn't run, then you have a problem in the DB wire between the relay and the PCM.((((((( DB is dark blue,DG is dark green.WT is white,BK is black.)).--------------- This troubleshooting will help to confirm the fault.
-------------
If in case you require another working PCM. Click this link directly:---
http://cgi.ebay.com/ebaymotors/98-Grand-Cherokee-4-0-ECU-Engine-Computer-56044513AC-/280620208993#ht_1362wt_752
----------
This should help.Thanks.Helpmech.
Its possible that you can find this details in the Jeep-ZJ-Grand-Cherokee-Secc-8W-Wiring-Diagrams
Keep us updated.
The Powertrain Control Module (PCM) (the computer) is located on the right firewall directly behind the glove box inside the engine compartment. These control modules are somewhat expensive and have to contain the exact part numbers to accomodate all options. These must be programmed by the dealer.
1,904 views
Usually answered in minutes!
1998
jeep grand CHEROKEE LAREDO ZJ 4.0 ENGINE
PCM/ECM INTERNAL CIRCUIT SCHEMATIC NEEDED.
Please note that ONLY 1997 and 1998 YEARS MATCH PCM/ECM PART NUMBER 56044513AC
I have a bad circuit inside the PCM/ECM controlling the fuel gauge reading of empty all the time. Scan tool shows that the fuel gauge works through full range and turns low fuel light off during scan. I can repair to board level once I have the schematic!
I have already determined that the fuel gauge circuit inside the ECM/PCM is bad and that is why I'm looking for a internal schematic for part number 56044513AC on a 1998 Jeep Grand with a 4.0 engine automatic. ONLY 1997 and 1998 had this part number PCM/ECM.
INTERNAL schematic for 1998 PCM/ECM JEEP PART NUMBER 54044513AC
I know about bad cap's and it does me no good without a schematic as I can repair to board level. Please note that a 1993 jeep wire diagram of outside connectors is not what I'm asking for as well as telling me to replace the whole unit as well as telling me what general component failure looks like! The board is covered in sealant and I need the schematic and will continue to repost until someone answers with a schematic or I want my $20 back
×