What is the SPN3226 fault?
2 Answers
SPN3226 fault code indicates that the emissions are not up to standard, and the urea supply system needs to be checked for proper functioning. Below is the relevant introduction: 1. Name Origin: The technical name for automotive urea is Diesel Exhaust Fluid (DEF), commonly referred to in China as automotive urea, vehicle urea, or vehicle denitrification agent. Automotive urea solution was first used in Europe, where it is called AdBlue, while in North America, it is known as DEF (Diesel Exhaust Fluid). It should be noted that there are urea manufacturers abroad with AdBlue and DEF certifications, which adhere to strict international standards, whereas very few domestic enterprises in China have obtained AdBlue or DEF certification. 2. Composition: Automotive urea solution is a colorless, transparent, and clear liquid with a concentration of 31.8% to 33.2%, used for reducing NOx emissions. Currently, the automotive urea solution in use is generally composed of 32.5% high-purity urea and 67.5% deionized water.
I've encountered the SPN3226 fault several times. I remember that winter when I was driving to go camping, the dashboard suddenly lit up with a warning light, and after checking, it turned out to be this code. It indicates a coolant temperature sensor circuit issue, simply put, the sensor signal is too low, which could be due to a faulty probe, aging or loose wiring, or corroded connectors. That time, I opened it up to inspect and found that the connector wasn't plugged in tightly. Reconnecting it fixed the issue, but I still replaced the sensor later just to be safe. Ignoring this problem can lead to engine overheating or even cylinder scoring, potentially doubling the repair costs. I recommend keeping an OBD diagnostic tool handy to check the codes yourself first, but always ensure the engine is cold before working on it—safety first. However, for complex wiring issues, it's best to leave them to professional auto repair shops.
