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Discussion Starter #1
Hi everyone. So I’m attempting to get an 04 Deville I have in driveable shape ( been sitting a while) to sell. Put a fresh battery in around a week ago, everything worked great, cranked great, had no fuel pressure. Moving forward to yesterday, I installed a new pump car fired right up. Moved it out of the hole it was in and backed it in front of the garage door and shut it off. Attempted to restart and I’m missing a lot of functions now.
Things that work: power seats, exterior lights, blinkers, hvac, partial cluster, wipers.

Things not working: radio, windows, no gauge readings or prndl, no power locks or trunk release, no crank. Can’t communicate with pcm, verified power and grounds on the obd2 port.

I’ve verified battery voltage and power on all of the fuses associated with the non functional. Checked both fuse blocks for corrosion and verified all grounds. Anyone have wiring diagrams for some of these things? I could only find powertrain management on AllData which isn’t helping.
 

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2003 Deville Base
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5,056 Posts
Welcome to the forums! Have you attempted to pull codes? If not use the car's built in scanner to pull codes. They will be a letter and four digits, followed by "Current" or "History" Post the codes in this thread ALONG WITH the definitions and you'll likely get plenty of advice. If you don't know how to pull codes, see the sticky thread at the top of the Deville page.
 

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Discussion Starter #3
pcm won’t communicate with my scanner to pull. Will try to pull using the built in feature tomorrow.
 

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Discussion Starter #4
So had some more time today to mess with the caddy. Entire can network will not communicate. Does anyone have a diagram or know where the splice point is for all of the modules?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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The OBD-II port is fused. Check the legends in the fuse/relay boxes - inside the box tops.

Use the correct year/model group of instructions in the "How to pull codes" sticky - the section by JimD. Then use the OBD-II code definitions link to post what you found.

There is no "splice point" for modules. The 188 pins in the connectors on the PCM are the
central hub - don't go there. All sensor data rides on the car's serial data bus, part of the original sound system head unit.

data link connector.gif
 

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Discussion Starter #6
I’ve been over both fuse blocks twice. Every module is dead. Obd2 port is working as intended, modules just won’t communicate. Assuming one module is shorted and killing the can network. I found a random tech article stating all of the modules have a junction point. “Sp300” is the label as far as diagrams go, I just can’t find the diagram. Built in scanner doesn’t function either.
 

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Discussion Starter #7
Just wanted to give an update. Purchased the service manual from identifix and found some decent diagrams. Ended up finding a broken wire in one of the splice packs. Repaired wire and everything came back to life. Fuel pumps dead again already, $40 eBay pump but I still suspect another electrical gremlin on the pump circuit.
583327
 
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