VW Crafter Cooling System Failure Linked to ECU Fault

I had a similar issue with my VW Transporter T5 2015 diesel. As someone with moderate experience in car maintenance, I initially thought it was just a coolant leak, but the diagnostic codes suggested deeper control module communication problems. The check engine light and overheating were caused by a damaged wiring connection between the engine control module and the cooling system sensors. The CAN bus system wasnt receiving accurate temperature readings, causing the cooling system to malfunction. The workshop found the root cause through car diagnostics, a corroded plug connection affecting the data link to the coolant temperature sensor. They replaced the damaged wiring harness section and cleaned the connector pins. Total repair cost was 95€, which included diagnostic testing and the wiring repair. To properly assist with your case, could you share: Current coolant temperature readings, Specific diagnostic trouble codes, Whether the issue occurs more during idle or while driving, If you notice any correlation with outside temperature This information would help determine if your Crafter is experiencing the same control module communication issue I encountered with my Transporter. Make sure to have a proper diagnostic scan done before any repairs, as similar symptoms can stem from different root causes in the cooling system.

Latest service was performed at 108000KM and included cooling system inspection and engine diagnostics. A connectivity issue was identified in my Crafter too, you correctly pointed to wiring concerns. The root problem turned out to be moisture infiltration in the main wiring harness connector behind the battery tray, causing intermittent communication failures in the control unit. The diagnostic trouble codes initially pointed to a temperature sensor malfunction, but after thorough car diagnostics, the technician found corrosion affecting multiple pins in the engine control module connector. The repair involved cleaning the connections, applying dielectric grease, and installing a protective cover to prevent future water damage. Total repair cost was 180€ including parts and labor. The overheating and check engine light issues disappeared completely after fixing the wiring issue. One key learning: these symptoms dont always mean coolant leaks or mechanical problems, electronic control systems can cause similar behavior when compromised.

Thanks for sharing those details, really helpful to hear about your successful repair. My Transporter had nearly identical symptoms, and I went through a similar diagnostic process. The moisture damage to connectors seems to be a common weakness in these models. The repair cost difference makes sense, my 95€ job was simpler since the corrosion was limited to a single sensor connection. Your 180€ repair addressing multiple corroded pins and adding protective measures was money well spent for a permanent fix. A key insight from both our cases: when control module communication fails, the system defaults to incorrect coolant management, leading to pressure buildup and overheating. The diagnostic trouble codes were crucial in pointing to a wiring issue rather than a mechanical cooling system problem. For anyone else seeing these symptoms: have a professional check the wiring and connections first, especially around the battery area where moisture tends to accumulate. Simple connectivity issues can mimic major cooling system failures. Have you noticed any other electrical gremlins clear up after the repair? In my case, several minor warning lights I had ignored also disappeared once the wiring was sorted.

Having the repair complete and running tests for a few weeks now, I can confirm the fix resolved multiple issues beyond just the cooling system. Several warning lights that would out of nowhere appear on the dashboard have stopped, and the engine performance feels more consistent overall. The technician explained that the CAN bus connectivity problems were affecting more than just the cooling system readings. My diagnostic trouble codes also showed unusual transmission and fuel system errors that disappeared after fixing the corroded wiring connections in the control unit. For the record, here are the key stats from my repair: Total runtime since fix: 3 weeks, Operating temperature now stays steady at normal levels, No more coolant pressure issues or leaks, Check engine light remains off, Repair cost: 180€ The car diagnostics definitely saved me from replacing parts unnecessarily. Without proper testing, I might have ended up changing the water pump or thermostat when the real issue was just compromised wiring affecting the control unit communication. Looking back, the symptoms perfectly matched what others described, this seems to be a common connectivity issue worth checking first before assuming mechanical problems.