2000 Chevrolet Venture Won't Start with P1626 and U1000 Fault Codes - Passlock & Security System Issue
Hi, I'm looking for help diagnosing a starting issue on my 2000 Chevrolet Venture. The vehicle has a P3 Passlock system and was recently attempted to be stolen — as a result, the steering column was replaced. After installing the original passkey and ignition in the new column, it ran fine for about a month. Then suddenly, the security light came on and remained lit. I used my Craftsman scan tool to check for fault codes, which showed P1626 and later only P1626 and U1000 after clearing the previous ones. The vehicle now will not start at all. I've tried all standard relearn procedures: lock/unlock/open/shut cycles, 3-minute key-on sequences, and full ignition cycle resets — but nothing has resolved the issue. As a DIYer with limited experience, I'm at my wits' end. The original owner's manual and older car tech were much simpler than today’s systems. I've seen suggestions about using a toggle switch on the security wire, but I’m unsure if this applies to my vehicle — my security wire is pink, not yellow. Any guidance or troubleshooting steps would be greatly appreciated. I'm trying to avoid professional help due to cost and time constraints. Thanks in advance for any advice!
The U1000 code indicates a communication failure between the Powertrain Control Module (PCM) and the Body Control Module (BCM). Without a dedicated scanner like TechII, it's difficult to provide specific DIY solutions. There are no aftermarket remote starters or added electrical components in this vehicle — so the issue is likely rooted in either module connectivity or power supply.