1988manche Posted October 26, 2018 Share Posted October 26, 2018 I had a topic a few days ago about this but did some more testing on it. I have a fresh 97+ swap and when i hook up the battery my lights on the dash are on but my odometer doesnt work. If i turn the key to run the lights turn off. If i try and crank it i get nothing. I found this test and ran it and my numbers where way out of range, it says if your resistance is below 60 it could be the pcm or the wiring, is there anyway to pinpoint more if its the pcm before i spend some money on a new one? Link to comment Share on other sites More sharing options...
Dzimm Posted October 26, 2018 Share Posted October 26, 2018 Did you check all your wiring like mentioned in your other post? Did the parts come from a running XJ? Don't start replacing parts if you haven't checked the items you know you messed with. In this case, that's the wiring. The chances of the computer being bad are slim. The chances of a loose connection or bad ground are high. Link to comment Share on other sites More sharing options...
1988manche Posted October 26, 2018 Author Share Posted October 26, 2018 Yes i have gone through the wires and grounds multiple times already Link to comment Share on other sites More sharing options...
Dzimm Posted October 26, 2018 Share Posted October 26, 2018 Was the XJ running that you pulled the parts from? Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 26, 2018 Share Posted October 26, 2018 You never answered if the donor 97 was a running XJ. If unknown, you have no idea what you are working with. First thing I'd do is pull apart every electrical harness connection looking for unseated plugs, bent pins, then clean them all with contact cleaner. Any harness connectors or ground wires hanging? Link to comment Share on other sites More sharing options...
1988manche Posted October 26, 2018 Author Share Posted October 26, 2018 Nothing hanging and everything came from a running xj except the engine harness and pcm Link to comment Share on other sites More sharing options...
Dzimm Posted October 26, 2018 Share Posted October 26, 2018 2 hours ago, 1988manche said: Nothing hanging and everything came from a running xj except the engine harness and pcm In that case, check the wiring again. The chances of a bad computer are slim. Trace EVERY wire, remove ALL connectors and clean them, remove and clean ALL grounds. Especially important are the grounds on the drivers fender, firewall, engine block, and the drivers footwell. Inspect all the wires you can find to look for any nicks or corrosion, use your multimeter to test continuity on as many wires as you can. It's a tedious process but you have to be 100% sure your wiring is good. There is a lot of places you can easily nick or pinch a wire while doing the 97+ swap. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 26, 2018 Share Posted October 26, 2018 3 hours ago, 1988manche said: Nothing hanging and everything came from a running xj except the engine harness and pcm Where did your PCM come from, and what is the part number? Link to comment Share on other sites More sharing options...
1988manche Posted October 26, 2018 Author Share Posted October 26, 2018 40 minutes ago, HOrnbrod said: Where did your PCM come from, and what is the part number? Ill look at it and let ya know Link to comment Share on other sites More sharing options...
1988manche Posted October 26, 2018 Author Share Posted October 26, 2018 1 hour ago, Dzimm said: In that case, check the wiring again. The chances of a bad computer are slim. Trace EVERY wire, remove ALL connectors and clean them, remove and clean ALL grounds. Especially important are the grounds on the drivers fender, firewall, engine block, and the drivers footwell. Inspect all the wires you can find to look for any nicks or corrosion, use your multimeter to test continuity on as many wires as you can. It's a tedious process but you have to be 100% sure your wiring is good. There is a lot of places you can easily nick or pinch a wire while doing the 97+ swap. Any good place to look at what wires on everything i need to probe to test continuity or should every wire have it with the key on? Link to comment Share on other sites More sharing options...
zomeizter Posted October 26, 2018 Share Posted October 26, 2018 All you need is electrical schematics, a test light/multimeter, and lots of patience. You need to verify the correct reading on grounds, battery, ignition, and crank scenarios for the respective leads. Once that is verified, move on to the reference/return voltage to all sensors. Continuity checks are done if you have a bad or non-existent reading, suspect an open circuit then. You got this, gitter dun! Link to comment Share on other sites More sharing options...
Dzimm Posted October 27, 2018 Share Posted October 27, 2018 18 hours ago, 1988manche said: Any good place to look at what wires on everything i need to probe to test continuity or should every wire have it with the key on? Continuity tests are done when the key is off. You put one probe on each end of a wire to test if the wire is broken in between or not. This is the test you should do in this case, on any wires you see a pinch, nick, corrosion, or aren't getting the proper power through. It tests the wires themselves to help narrow down any open circuits. The engine harness on XJs and MJs is susceptible to a lot of heat, vibration, dirt, oil, ect. I have rarely seen a harness that didn't have wires exposed or correded and since your harness came from an unknown Jeep, you should be checking those wires with a fine tooth comb after you triple check all the grounds and plugs. Link to comment Share on other sites More sharing options...
1988manche Posted October 28, 2018 Author Share Posted October 28, 2018 On 10/26/2018 at 3:17 PM, HOrnbrod said: Where did your PCM come from, and what is the part number? here's a pic of the pcm Link to comment Share on other sites More sharing options...
Dzimm Posted October 28, 2018 Share Posted October 28, 2018 11 minutes ago, 1988manche said: here's a pic of the pcm That's the correct ecu but is that dirt or rust? And what did the rest of the xj look like if that's all rust? Link to comment Share on other sites More sharing options...
1988manche Posted October 28, 2018 Author Share Posted October 28, 2018 32 minutes ago, Dzimm said: That's the correct ecu but is that dirt or rust? And what did the rest of the xj look like if that's all rust? Just a bunch of dirt Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 28, 2018 Share Posted October 28, 2018 56041537af PCM comes out as correct for: 98-01 Jeep Cherokee 4.0L ECU ECM PCM Engine Computer https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=56041537af&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=56041+537af Link to comment Share on other sites More sharing options...
1988manche Posted October 28, 2018 Author Share Posted October 28, 2018 So looking into the wiring more made me realize that the jeep i got the interior wiring harness from had a remote start hooked up, could not having that in be a cause of my problem? Link to comment Share on other sites More sharing options...
Dzimm Posted October 28, 2018 Share Posted October 28, 2018 2 hours ago, 1988manche said: So looking into the wiring more made me realize that the jeep i got the interior wiring harness from had a remote start hooked up, could not having that in be a cause of my problem? That's a big sign someone messed with the wiring at some point. From what you describe for issues I am willing to bet the wiring is jacked up because of the missing remote start and not being put back to factory. Link to comment Share on other sites More sharing options...
1988manche Posted October 28, 2018 Author Share Posted October 28, 2018 50 minutes ago, Dzimm said: That's a big sign someone messed with the wiring at some point. From what you describe for issues I am willing to bet the wiring is jacked up because of the missing remote start and not being put back to factory. Honestly at this point I'm about to buy a new harness, i got the radio working but it only comes on with the key in the off position, something is messed up with the wiring Link to comment Share on other sites More sharing options...
Dzimm Posted October 28, 2018 Share Posted October 28, 2018 Just now, 1988manche said: Honestly at this point I'm about to buy a new harness, i got the radio working but it only comes on with the key in the off position, something is messed up with the wiring You could pull the harness back out and lay it on the ground and use a factory wiring diagram to go through it and repair anything that's been chopped up. Even just looking at it you should be able to see what isn't factory. Otherwise yeah a harness that's not hacked up to begin with would help. Link to comment Share on other sites More sharing options...
shelbyluvv Posted October 29, 2018 Share Posted October 29, 2018 Check your transmission harness. That's what caused my 1694 code Link to comment Share on other sites More sharing options...
1988manche Posted November 4, 2018 Author Share Posted November 4, 2018 Ok so a little update, put a new dash harness and now the dash is working and so is the radio, still getting the no bus code but does anyone know what these two connectors go into? Link to comment Share on other sites More sharing options...
AZJeff Posted November 5, 2018 Share Posted November 5, 2018 23 hours ago, 1988manche said: Ok so a little update, put a new dash harness and now the dash is working and so is the radio, still getting the no bus code but does anyone know what these two connectors go into? You need the FSM for a late-model XJ to help you identify connectors. There is a specific section that shows the "pin-outs" and shape of each connector. If you don't have a manual, I can burn a CD of mine and send it to you. Link to comment Share on other sites More sharing options...
1988manche Posted November 5, 2018 Author Share Posted November 5, 2018 4 hours ago, AZJeff said: You need the FSM for a late-model XJ to help you identify connectors. There is a specific section that shows the "pin-outs" and shape of each connector. If you don't have a manual, I can burn a CD of mine and send it to you. That would be awesome if you could, i don't have one Link to comment Share on other sites More sharing options...
AZJeff Posted November 6, 2018 Share Posted November 6, 2018 16 hours ago, 1988manche said: That would be awesome if you could, i don't have one Send me your postal address via the message system on the forum, and I will mail you a CD of the shop manual. Link to comment Share on other sites More sharing options...
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