VW Taigo Cooling System Failure Linked to Control Unit

Had a very similar issue with my 2020 VW T-Cross which I solved last summer. Having some experience with cooling system problems, I can share what worked in my case. The symptoms matched yours exactly, overheating engine, check engine light, and coolant leaks. Initial car diagnostics revealed a CAN bus communication fault between the cooling system control module and the engine management unit. The problem was eventually traced to a damaged wiring connection near the coolant temperature sensor. The workshop found that moisture had corroded one of the connector pins, causing intermittent communication failures. This created incorrect temperature readings, leading to improper coolant pressure management. The repair involved replacing the wiring harness connector and recalibrating the control module, costing 95€ including labor. The entire fix took about 2 hours at the workshop. Since then, no more issues with the cooling system or error messages. Before suggesting specific solutions for your case, could you share: Have you noticed any correlation between the issues and specific driving conditions? What error codes is your diagnostic system showing? Did these problems start suddenly or develop gradually? Has any recent maintenance work been done on the cooling system? This information would help determine if your issue stems from a similar wiring issue or if there might be other factors involved.

Had a very similar issue with my 2020 VW T-Cross which I solved last summer. Having some experience with cooling system problems, I can share what worked in my case. The symptoms matched yours exactly, overheating engine, check engine light, and coolant leaks. Initial car diagnostics revealed a CAN bus communication fault between the cooling system control module and the engine management unit. The problem was eventually traced to a damaged wiring connection near the coolant temperature sensor. The workshop found that moisture had corroded one of the connector pins, causing intermittent communication failures. This created incorrect temperature readings, leading to improper coolant pressure management. The repair involved replacing the wiring harness connector and recalibrating the control module, costing 95€ including labor. The entire fix took about 2 hours at the workshop. Since then, no more issues with the cooling system or error messages. Before suggesting specific solutions for your case, could you share: Have you noticed any correlation between the issues and specific driving conditions? What error codes is your diagnostic system showing? Did these problems start suddenly or develop gradually? Has any recent maintenance work been done on the cooling system? This information would help determine if your issue stems from a similar wiring issue or if there might be other factors involved.

Had a very similar issue with my 2020 VW T-Cross which I solved last summer. Having some experience with cooling system problems, I can share what worked in my case. The symptoms matched yours exactly, overheating engine, check engine light, and coolant leaks. Initial car diagnostics revealed a CAN bus communication fault between the cooling system control module and the engine management unit. The problem was eventually traced to a damaged wiring connection near the coolant temperature sensor. The workshop found that moisture had corroded one of the connector pins, causing intermittent communication failures. This created incorrect temperature readings, leading to improper coolant pressure management. The repair involved replacing the wiring harness connector and recalibrating the control module, costing 95€ including labor. The entire fix took about 2 hours at the workshop. Since then, no more issues with the cooling system or error messages. Before suggesting specific solutions for your case, could you share: Have you noticed any correlation between the issues and specific driving conditions? What error codes is your diagnostic system showing? Did these problems start suddenly or develop gradually? Has any recent maintenance work been done on the cooling system? This information would help determine if your issue stems from a similar wiring issue or if there might be other factors involved.

Thanks for sharing your experience. My Taigo has just had its 130000km service last month which involved a full cooling system inspection. The issues started appearing shortly after, so I suspect there might be a connection. The diagnostic tool shows error code P0128 and a data link error in the engine control module. Interestingly, the problems mostly occur during highway driving, less so in city traffic. The temperature gauge fluctuates erratically when this happens. The cooling system pressure issues and control unit communication errors began suddenly, just a week after the service. My mechanic suggested a software glitch might be causing the control unit to misread temperature sensors, but I wanted to check if others had similar experiences before committing to repairs.

Thanks for sharing your experience. My Taigo has just had its 130000km service last month which involved a full cooling system inspection. The issues started appearing shortly after, so I suspect there might be a connection. The diagnostic tool shows error code P0128 and a data link error in the engine control module. Interestingly, the problems mostly occur during highway driving, less so in city traffic. The temperature gauge fluctuates erratically when this happens. The cooling system pressure issues and control unit communication errors began suddenly, just a week after the service. My mechanic suggested a software glitch might be causing the control unit to misread temperature sensors, but I wanted to check if others had similar experiences before committing to repairs.

Thanks for sharing your experience. My Taigo has just had its 130000km service last month which involved a full cooling system inspection. The issues started appearing shortly after, so I suspect there might be a connection. The diagnostic tool shows error code P0128 and a data link error in the engine control module. Interestingly, the problems mostly occur during highway driving, less so in city traffic. The temperature gauge fluctuates erratically when this happens. The cooling system pressure issues and control unit communication errors began suddenly, just a week after the service. My mechanic suggested a software glitch might be causing the control unit to misread temperature sensors, but I wanted to check if others had similar experiences before committing to repairs.

Thanks for the additional details. Based on what you describe, your symptoms align closely with what I experienced, but there are some key differences. After the service on my T-Cross, I also noticed similar control module communication errors. However, in my case, the diagnostic trouble code was different, pointing specifically to the wiring issue mentioned earlier. Your P0128 code combined with the data link error suggests a more complex interaction between the control unit and temperature monitoring systems. The timing after the service is particularly telling, on my vehicle, a technician later discovered that during routine maintenance, a connector had been accidentally pinched, creating intermittent signal issues. The highway-specific symptoms are significant. When my car showed similar behavior, the higher speeds and increased engine load made the control unit communication problems more apparent. The erratic temperature gauge readings match what I experienced before the repair. Given these patterns, a software glitch in the control module is certainly possible, but I would recommend having the service center specifically check: All sensor connections that were disturbed during the recent service, The integrity of the coolant temperature sensor wiring, The ground connections for the engine control module My final repair ended up being simpler than initially suspected, though the diagnostic process took longer than the actual fix. The total cost for diagnosing and resolving the control unit issues came to 180€.

Thanks for the additional details. Based on what you describe, your symptoms align closely with what I experienced, but there are some key differences. After the service on my T-Cross, I also noticed similar control module communication errors. However, in my case, the diagnostic trouble code was different, pointing specifically to the wiring issue mentioned earlier. Your P0128 code combined with the data link error suggests a more complex interaction between the control unit and temperature monitoring systems. The timing after the service is particularly telling, on my vehicle, a technician later discovered that during routine maintenance, a connector had been accidentally pinched, creating intermittent signal issues. The highway-specific symptoms are significant. When my car showed similar behavior, the higher speeds and increased engine load made the control unit communication problems more apparent. The erratic temperature gauge readings match what I experienced before the repair. Given these patterns, a software glitch in the control module is certainly possible, but I would recommend having the service center specifically check: All sensor connections that were disturbed during the recent service, The integrity of the coolant temperature sensor wiring, The ground connections for the engine control module My final repair ended up being simpler than initially suspected, though the diagnostic process took longer than the actual fix. The total cost for diagnosing and resolving the control unit issues came to 180€.

Thanks for the additional details. Based on what you describe, your symptoms align closely with what I experienced, but there are some key differences. After the service on my T-Cross, I also noticed similar control module communication errors. However, in my case, the diagnostic trouble code was different, pointing specifically to the wiring issue mentioned earlier. Your P0128 code combined with the data link error suggests a more complex interaction between the control unit and temperature monitoring systems. The timing after the service is particularly telling, on my vehicle, a technician later discovered that during routine maintenance, a connector had been accidentally pinched, creating intermittent signal issues. The highway-specific symptoms are significant. When my car showed similar behavior, the higher speeds and increased engine load made the control unit communication problems more apparent. The erratic temperature gauge readings match what I experienced before the repair. Given these patterns, a software glitch in the control module is certainly possible, but I would recommend having the service center specifically check: All sensor connections that were disturbed during the recent service, The integrity of the coolant temperature sensor wiring, The ground connections for the engine control module My final repair ended up being simpler than initially suspected, though the diagnostic process took longer than the actual fix. The total cost for diagnosing and resolving the control unit issues came to 180€.

Based on your insight, I think the post-service timing is too coincidental to ignore. The P0128 code and data link errors, combined with the highway-specific overheating, really point toward a connectivity issue introduced during maintenance. Your experience with the pinched connector seems highly relevant to my situation. The erratic temperature gauge behavior matches what you described, and since my issues also worsen under highway load, I suspect a similar root cause. The sudden onset after service further supports this theory. My main concern was a major component replacement, but your case suggests checking the wiring and connections first makes more sense. I will have the shop inspect all the sensor connections and control module grounds before exploring more complex solutions. The diagnostic trouble codes seem to align with communication problems rather than mechanical failure. If the repair cost ends up around 180€ like in your case, that would be far better than replacing major cooling system components. I will schedule an appointment focused specifically on checking these connectivity issues. The car diagnostics pointing to a control unit error rather than a physical cooling system failure gives me hope this can be resolved without extensive repairs.

Based on your insight, I think the post-service timing is too coincidental to ignore. The P0128 code and data link errors, combined with the highway-specific overheating, really point toward a connectivity issue introduced during maintenance. Your experience with the pinched connector seems highly relevant to my situation. The erratic temperature gauge behavior matches what you described, and since my issues also worsen under highway load, I suspect a similar root cause. The sudden onset after service further supports this theory. My main concern was a major component replacement, but your case suggests checking the wiring and connections first makes more sense. I will have the shop inspect all the sensor connections and control module grounds before exploring more complex solutions. The diagnostic trouble codes seem to align with communication problems rather than mechanical failure. If the repair cost ends up around 180€ like in your case, that would be far better than replacing major cooling system components. I will schedule an appointment focused specifically on checking these connectivity issues. The car diagnostics pointing to a control unit error rather than a physical cooling system failure gives me hope this can be resolved without extensive repairs.

Based on your insight, I think the post-service timing is too coincidental to ignore. The P0128 code and data link errors, combined with the highway-specific overheating, really point toward a connectivity issue introduced during maintenance. Your experience with the pinched connector seems highly relevant to my situation. The erratic temperature gauge behavior matches what you described, and since my issues also worsen under highway load, I suspect a similar root cause. The sudden onset after service further supports this theory. My main concern was a major component replacement, but your case suggests checking the wiring and connections first makes more sense. I will have the shop inspect all the sensor connections and control module grounds before exploring more complex solutions. The diagnostic trouble codes seem to align with communication problems rather than mechanical failure. If the repair cost ends up around 180€ like in your case, that would be far better than replacing major cooling system components. I will schedule an appointment focused specifically on checking these connectivity issues. The car diagnostics pointing to a control unit error rather than a physical cooling system failure gives me hope this can be resolved without extensive repairs.