Volvo S40 Transmission Issue

The symptoms you describe certainly indicate a malfunction within the transmission system, potentially linked to the radiator oil pressure as indicated by your error codes. Have you inspected the wiring harness and connectors associated with the radiator pressure sensor for any signs of corrosion, damage, or loose connections? Ensuring a clean and secure electrical pathway is paramount before considering more invasive diagnostic procedures. Can you confirm the specific error codes you retrieved from the vehicle's computer?

Thanks for the quick reply! Yes, I did a visual inspection of the wiring harness and connectors, but to be honest, it was a cursory glance. I didn't see anything blatantly obvious, but I'll definitely take a closer look, paying specific attention to corrosion. The error code stored in the memory was related to the radiator oil pressure; can't remember the exact number right now. Any specific areas on the harness that are known to be problematic on these S40s?

Given the error code, and acknowledging your detailed inspection, I must strongly suggest consulting a certified Volvo technician for a comprehensive diagnostic evaluation. While a damaged cable or plug connection is plausible, further investigation may reveal more complex problems within the transmission system necessitating specialized tools and expertise. Continuing without proper guidance may exacerbate the situation. I advise arranging an appointment with your local workshop promptly.

Appreciate the insight. I spent some extra time cleaning all of the contacts. No improvement. In the end, I brought it into my trusted shop. Turns out it was a faulty plug as suspected, costing me 95€ with labor and tax included. Thanks again for your thoughts!