2010 VW Passat 2.0T TSI P2185 Code: Misfire, Black Smoke & Constant Radiator Fan Operation
I own a 2010 Volkswagen Passat 2.0T TSI with approximately 120,000 miles. I recently noticed unusual behavior after letting the car sit for about 1.5 weeks. When I started it on a cold day (around 28°F), it emitted black smoke and sounded like it was misfiring. After idling for about four minutes, the engine ran normally. I then moved the vehicle to wash it and turned off the engine. Upon attempting to restart it later, the car displayed a P2185 diagnostic code. Additionally, my radiator fan runs continuously whenever the ignition is on—even in accessory mode (key on, 'Christmas' lights illuminated). The fan also continues for about 10 seconds after turning off the engine before shutting down. I'm wondering what could be causing both the P2185 error and this persistent fan operation. Any insights or troubleshooting steps would be greatly appreciated.
A P2185 diagnostic code typically indicates one or more of the following issues: - A loose or faulty connection at the #2 Engine Coolant Temperature (ECT) sensor - An open ground circuit between the #2 ECT sensor and the Powertrain Control Module (PCM) - A short in the power supply line from the sensor to the PCM - A defective PCM (less common) - A damaged temperature sensor with an internal short For reference: https://www.vw-forums.com/p2185 Regarding the location of the #2 ECT sensor, it is typically found on the passenger-side cylinder head near the engine block. It's important to verify wiring connections and ensure proper grounding when diagnosing this code.