VW Crafter Water Sensor Issues Causing Engine Problems

I experienced a similar sensor issue with my 2009 VW Transporter 2.5 TDI. Having some experience with diesel engines, I recognized comparable symptoms, rough running, check engine light, and multiple error codes. The electrical fault turned out to be a damaged wiring connection to the water sensor. After car diagnostics, the workshop found corroded pins in the sensor plug. They cleaned the connection points and replaced the damaged wiring section. Total cost was 95€ for parts and labor. Before throwing parts at the problem, proper sensor testing is crucial. A faulty connection can mimic a bad sensor, which is what happened in my case. The fix has been reliable since then, with no recurring sensor fault codes. What specific error codes is your Crafter showing? This would help narrow down if your issue matches what I encountered. Also, can you confirm: Engine size and type, Any recent work done, Whether symptoms change with engine temperature, If the check engine light is solid or flashing This information would help determine if your sensor issue has the same root cause.

Last service was done at 75000KM, but these issues only started appearing recently. After getting your response, I pulled the error codes using a scanner. Getting P2263 and P0401 consistently. The check engine light stays solid, not flashing, and symptoms definitely get worse when the engine is cold. The auto electronics diagnostic shows intermittent sensor readings, especially during cold starts. When the engine warms up, the rough running improves slightly but never completely goes away. I noticed the sensor connector does look a bit weathered, so your suggestion about checking the electrical connections makes sense. Would you recommend testing the sensor connections first before replacing any parts? The water sensor itself costs 180€ at our local parts supplier, so I want to make sure thats actually the problem before spending the money.

Thanks for those details, those are exactly the error codes I saw on my Transporter before fixing the wiring issue. The symptoms match too, especially the cold start problems and intermittent sensor readings. Definitely test the connections first. The fact your moisture sensor readings are inconsistent but improve with engine warmth strongly suggests an electrical fault rather than a completely failed sensor. Heat often temporarily improves poor connections by expanding the metal contact points. Here is what worked for me: 1. Clean the sensor connector with electrical contact cleaner 2. Check for green corrosion on the pins 3. Test continuity in the wiring harness 4. Verify proper voltage at the sensor connection My mechanic found the wiring had rubbed through against a bracket, allowing moisture to create corrosion. The car diagnostics initially pointed to a bad sensor, but proper testing saved me from unnecessarily replacing the 180€ part. If cleaning and rewiring dont solve it, then consider sensor replacement. But start with the electrical connections, they are the most common failure point in these sensor systems and much cheaper to fix.

Thank you for the detailed troubleshooting suggestions. Just had my mechanic check the connections as you recommended. The moisture sensor wiring definitely showed signs of wear, with visible corrosion on two of the connector pins. We cleaned the contacts and repaired a section of damaged wire for 65€. The car diagnostics now show clean readings from the water sensor. Cold starts are smooth again, and the check engine light has stayed off for the past week. Really glad I checked the electrical fault possibilities before replacing the entire sensor unit. Saved over 100€ by focusing on the wiring issue first. Going to add checking sensor connections to my regular maintenance routine now. The mechanic mentioned these electrical faults are pretty common in older diesel engines, especially around the moisture sensor and other engine management sensors. Worth keeping an eye on the wiring condition to catch issues early. This was exactly the practical advice I needed. Car is running like new again without having to spend big money on parts.