03 to 05 PCM swap

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chrisp2493

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I have been over the wire diagrams and I did all the splicing to wires that shared a pin. Added the 4 necessary pins, and ran the grounds to a ground stud. I went over my wiring 2 or three times and everything was lined up correctly. Since I had to tear apart my truck about three times trying to troubleshoot, I'm alittle burnt out, so maybe when I get my motivation back I'll take everything apart, triple check my pins, pull a better wire, and add the connectors instead of straight solder by the sensors. Im sure it's probably a crossed wire, but I'm not kidding in saying how careful I was going over prints, tagging wires, writing down what I did, and triple checking everything. I probably made an error somewhere, I'm just hard pressed to find it. Maybe I still have a bad ground or the wire I used was bad.
 

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I have been over the wire diagrams and I did all the splicing to wires that shared a pin. Added the 4 necessary pins, and ran the grounds to a ground stud. I went over my wiring 2 or three times and everything was lined up correctly. Since I had to tear apart my truck about three times trying to troubleshoot, I'm alittle burnt out, so maybe when I get my motivation back I'll take everything apart, triple check my pins, pull a better wire, and add the connectors instead of straight solder by the sensors. Im sure it's probably a crossed wire, but I'm not kidding in saying how careful I was going over prints, tagging wires, writing down what I did, and triple checking everything. I probably made an error somewhere, I'm just hard pressed to find it. Maybe I still have a bad ground or the wire I used was bad.



Check the pins on the actual sensor. If you cut and soldered the connections. You could have crossed the wiring there. I've done it lol


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Check the pins on the actual sensor. If you cut and soldered the connections. You could have crossed the wiring there. I've done it lol


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I wired them like this
2 white wires pin 1 & 2- heater power and ground (this shouldn't be specific, just a simple resistor circuit, power in/power out...right?)
Gray and black (3&4) was sensor signal and sensor return. I'd have to check my diagrams to see where I landed them. These two are probably my problem somewhere.


I tested the two white wires with an ohmmeter, they are connected through a resistor internally.

Thanks for all your help, I really appreciate it. Maybe next week I'll get back to this. I don't know why these sensors are giving me such problems, everything else was actually very simple. I may still have a bad ground, I'll try to find a better spot also.
 

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I wired them like this
2 white wires pin 1 & 2- heater power and ground (this shouldn't be specific, just a simple resistor circuit, power in/power out...right?)
Gray and black (3&4) was sensor signal and sensor return. I'd have to check my diagrams to see where I landed them. These two are probably my problem somewhere.


I tested the two white wires with an ohmmeter, they are connected through a resistor internally.

Thanks for all your help, I really appreciate it. Maybe next week I'll get back to this. I don't know why these sensors are giving me such problems, everything else was actually very simple. I may still have a bad ground, I'll try to find a better spot also.



There should be no wires from the pcm to any sensor that are internally resisted. I'll look over some diagrams tomorrow and see what's up. I actually have a guy bringing me his truck next weekend to keep for a couple of weeks to do the conversion from 03-05 myself again.


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chrisp2493

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There should be no wires from the pcm to any sensor that are internally resisted. I'll look over some diagrams tomorrow and see what's up. I actually have a guy bringing me his truck next weekend to keep for a couple of weeks to do the conversion from 03-05 myself again.


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No I mean inside the sensor, the heater coil. I hooked them up to the ohmmeter just to make sure the two whites went together
 

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No I mean inside the sensor, the heater coil. I hooked them up to the ohmmeter just to make sure the two whites went together



Gotcha. Just testing the sensor.


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Ok now I think I have another weird problem. I went through my diablo to adjust some parameters, and my tcm isn't showing up. All I could adjust was the pcm variables. When I loaded my tunes it let me trans tune, and said it was loaded, now it's no where to be found. I haven't updated it or anything else in the last week since I installed, so idk why it's gone
 
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The truck is still shifting different then the original stock tune (it holds the shifts longer) so it doesn't make sense that I can't find the trans tuning to adjust things
 

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It didn't fail on the trans tune did it? When I didn't have wires connected properly it kept giving me a checksum error. It would flash the PCM but not the TCM.


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As far as I know, it tuned the trans, I got the trans tune complete screen and it showed the performance 93 tune loaded and performance trans tune loaded. Now I just can't find it on my diablo. I'm just not sure if I have to return it to stock to load another trans tune or not. Never had to deal with this with the 03 haha. But like I said, it still shifts differently then before so that leads me to believe it's tuned..
 

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You basically have to go in and retune it completely to do the trans. There's no "modifying" the trans tune. You basically have to go in and do performance tune and retune it, and while your in that screen when it takes you to the TCM , you modify everything there. That's the annoying thing about the older model rams, when you tune one thing, you always have to tune the other usually. That's if I remember correctly. I didn't do much to the TCM when I tuned my old 03. I just did PCM tuning and didn't jack with the TCM much.


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You basically have to go in and retune it completely to do the trans. There's no "modifying" the trans tune. You basically have to go in and do performance tune and retune it, and while your in that screen when it takes you to the TCM , you modify everything there. That's the annoying thing about the older model rams, when you tune one thing, you always have to tune the other usually. That's if I remember correctly. I didn't do much to the TCM when I tuned my old 03. I just did PCM tuning and didn't jack with the TCM much.


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Ok awesome that's what I was looking for. I had a feeling that could be the problem, but didn't feel like taking the time to return to stock then completely retune. I'm debating about raising the 1-2 shift to 5900 rpms, but not sure if I should do that until I replace all the valve springs
 

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Question: does your truck have a black key or a grey key and use a SKIM module?
I got this guys truck on Saturday and he didn't tell me his truck had a grey key. Not I'm fumbling around figuring out how I'm gonna get the truck to run after the swap since it has the skim module and it will disable to pcm because it's not gonna have the right key to start the vehicle. Has anyone ever had the SKIM module tuned out with CMR to bypass the security system? This sucks lol. I don't wanna really start this swap if it's not gonna work because of the stupid ignition key and security module :(


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Mine had the black key, I didn't have any of that trouble. I asked this question on Hemi truck club, one of the cmr's said he could tune it out. But I would directly contact whoever is tuning for you to make sure they can. The only problem is the truck would probably have to have a custom tune for the rest of it's like to work properly
 
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Now a quick update on my issues. I started to redo the oxygen sensors this weekend. I bought new 16guage wire, two quick connectors, and pulled apart the pcm harnesses to double check my wiring pinouts. All of my pinouts were 100% correct according to the diagrams, no wires were in the wrong holes. I stopped at a junkyard to try to find an oem side o2 sensor connector off a vehicle, but was told every thing gets cut off the vehicles when they chop off the cats. Didn't even let me go look for myself, just told me nothing was available. Since I had already cut the connector off my sensor, I crimped a new 4 wire connector, aluminum sensor wire to copper connector. Then I soldered the other half of the copper connector to the copper feed wire. Then I soldered the feed wire to the pin wire in the harness. Started the truck up an no change at all, still getting heater circuit high, bank 2/1 and the truck will barely idle, drive and it will stall out. Disconnect the sensor and it runs perfectly. So today as my last ditch effort, I'm going to buy a brand new sensor, and run to summit racing to get a Casper electronics o2 extender harness to use the quick connect off of that. My only guess to the problem now is the aluminum to copper crimp is causing a high resistance connection and messing up the a/f ratio. I had no idea a sensor could be so picky with the wiring
 

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Now a quick update on my issues. I started to redo the oxygen sensors this weekend. I bought new 16guage wire, two quick connectors, and pulled apart the pcm harnesses to double check my wiring pinouts. All of my pinouts were 100% correct according to the diagrams, no wires were in the wrong holes. I stopped at a junkyard to try to find an oem side o2 sensor connector off a vehicle, but was told every thing gets cut off the vehicles when they chop off the cats. Didn't even let me go look for myself, just told me nothing was available. Since I had already cut the connector off my sensor, I crimped a new 4 wire connector, aluminum sensor wire to copper connector. Then I soldered the other half of the copper connector to the copper feed wire. Then I soldered the feed wire to the pin wire in the harness. Started the truck up an no change at all, still getting heater circuit high, bank 2/1 and the truck will barely idle, drive and it will stall out. Disconnect the sensor and it runs perfectly. So today as my last ditch effort, I'm going to buy a brand new sensor, and run to summit racing to get a Casper electronics o2 extender harness to use the quick connect off of that. My only guess to the problem now is the aluminum to copper crimp is causing a high resistance connection and messing up the a/f ratio. I had no idea a sensor could be so picky with the wiring



As long as your PCM wiring is good, it makes it sound like the sensor is at fault. Something is shorting something. It's not liking it.

But thanks for the info on the key issue. My tuner uses CMR and he says there is an option for SKIM "no/yes" options. So I guess first thing I'll do is have him turn skim off and see what happens. Otherwise this guy will have to buy a new skim module and a new key.


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As long as your PCM wiring is good, it makes it sound like the sensor is at fault. Something is shorting something. It's not liking it.

But thanks for the info on the key issue. My tuner uses CMR and he says there is an option for SKIM "no/yes" options. So I guess first thing I'll do is have him turn skim off and see what happens. Otherwise this guy will have to buy a new skim module and a new key.


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Yep, that slim issue was what had me scared about doing the swap. Luckily I had no issues.
One quick way to find out, just plug in the computer now and see if it will start. You don't need the tcm wires to start the truck. That's what I did just to see if it worked
 

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Yep, that slim issue was what had me scared about doing the swap. Luckily I had no issues.
One quick way to find out, just plug in the computer now and see if it will start. You don't need the tcm wires to start the truck. That's what I did just to see if it worked



I gotta get the guy to send me a tuner. He didn't bring one nor did he have one lol I was like uh? How do u want me to tune the truck? Hahah

So he's either gonna find one on Craigslist or send me a new one. I told him a predator would work. I told him if I could find one I'd get it for him.


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Redid all the wiring today, still no change in how it runs. I tested the voltage on the heater circuit and I only have 4 volts. I don't know why that's so low but I think that's causing the problems. I have no idea how to fix that
 

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Redid all the wiring today, still no change in how it runs. I tested the voltage on the heater circuit and I only have 4 volts. I don't know why that's so low but I think that's causing the problems. I have no idea how to fix that



You have to have something wrong/crossed or pinched somewhere. Unless the PCM you got is just bad. Not likely really.


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