Hello, my sisters Uplander was not starting a few weeks ago so I went to take a look. Nothing was happening when you turned the key. So obviously I replaced the battery, still nothing. Crawled under and tapped the starter and eventually got the van to start. A few days later no start again so this time I replaced the starter. There was also a code for oil pressure switch that I changed while the starter was out. Van ran ok for about a week then it would shut off while driving and not want to start. No codes so I started some research and found that there might be something wrong with the Passkey 3 system. Found some videos to bypass that with a resistor but none of that worked. Have changed the ignition switch, the Passkey device itself. Tried a key relearn and nothing seems to work. The key relearn is weird because the security light should stay on for the 10 min, but hers always goes off after a few seconds. I’ve checked fuses and relays and they look good. I’m out of ideas other then to pull the starter off again and check it! Any help from anyone would be greatly appreciated!!!!!!! Thank you!!

 

Worked on a few things like trying to jump the Crank relay and was able to get the starter to engage. So the problem must be between the BCM to the ECM. Today I messed around a bit after work, took the BCM out to see if it had and visual damage. Everything looked good, hooked it back up. Was check voltage to the ignition switch when the van disabled itself. No security light but I know it’s disabled because there is no light showing it’s in park and gas gauge stays at empty. Decided to unplug battery to reset things. Plugged battery back up got things to light up and just for fun decided to close the drivers door and the van started up. Ran ok for a few minutes then wanted to cut out. Ran a minute or two like that and finally shut off. But while it was running I got the scan tool on it and a bunch of code for lost communication to BCM, ECM, HVAC. Long story short, I must have a bad wire somewhere not sure why the drivers door made any difference my guess is where the wires go through the firewall! So looks like I keep digging!!!!

 

Welcome from Florida and good luck in your investigation!

 

Found some green crusty wire heading into the ECM module!!!!