VW Caddy Won't Stay Running: Immobilizer Alert

Had a very similar issue with my 2006 VW Golf gasoline. As someone with some hands-on experience working on VWs, this sounds exactly like what I encountered with the car immobilizer system. The anti-theft system was acting up because of incorrect key programming. The security light staying on is a classic symptom. Initially thought it was the key signal itself, but after having it checked, the issue was in the programming. Took it to a workshop specializing in car key programming and immobilizer repairs. They ran diagnostics and reprogrammed the key to properly communicate with the immobilizer system. Total cost was 45€ for the programming service. The car started running perfectly after that. Before suggesting more specific solutions, could you share: Have you tried using a spare key? What exact error codes are you getting? Has there been any recent work done on the electrical system? Did you replace or repair anything related to the remote start system recently? These details would help narrow down if your issue matches what I experienced with my Golf or if its something else in the anti-theft system.

Thanks for the input. Latest service was at 138269km with a full maintenance check. Just tried the spare key and getting the same behavior, engine turns over briefly then dies with the security light staying on. The stored codes are P1612 and P1613 which seem to point toward the immobilizer control module according to the scan tool. No recent electrical work or changes to the remote system. The ignition control module was checked during the last service and everything tested fine then. The problem started suddenly yesterday without any warning signs. Based on your experience, it does sound like a similar issue. Did your workshop do any additional tests before the key reprogramming to confirm it was an anti-theft system problem rather than a failing component?

Based on those error codes and symptoms, this is definitely matching what I experienced with my Golf. The sudden onset without warning is also exactly how mine failed, was working fine one day, then complete immobilizer lockout the next. Those P1612/P1613 codes are classic immobilizer fault indicators. In my case, the workshop ran a full diagnostic on the immobilizer control module before proceeding with the key programming fix. They found communication errors between the key transponder and the module, even though both components were technically functional. One key difference though, if both your main and spare keys are showing identical symptoms, its more likely pointing to an issue with the immobilizer control module itself rather than just key programming like in my case. The security light behavior confirms this. From my repair experience, would recommend: 1. Have the immobilizer control module specifically tested 2. Get the full diagnostic report before authorizing repairs 3. Make sure they check the wiring connections to the module The fix might end up being more involved than my simple key reprogramming. Module replacement with programming typically runs 200-300€ if thats needed. But start with proper diagnostics to avoid replacing parts unnecessarily. Just wondering, has the security light pattern changed at all when attempting to start (flashing vs solid)?

Thanks for the detailed info. Yes, the security light pattern has changed, it used to flash briefly during normal starts but now stays solid when trying to start. Your repair experience matches what the local shop just told me over the phone. They quoted 280€ for a new immobilizer control module plus programming if needed. Said they would do a full system diagnostic first though before replacing anything. Going to have it towed in tomorrow morning for testing. Really hoping its just a programming issue like yours was, but with both keys failing and that solid security light, I suspect youre right about the control module being the culprit. Will update once I get the official diagnosis. Thanks again for walking through your similar experience, helped confirm this is likely an anti-theft system problem rather than something in the engine management.