Peugeot 407 Oil Sensor Error

Sounds like a sensor issue alright. Have you tried checking the sensor's connector? Sometimes they get corroded or loose. If the oil level is correct when you check it manually, then it's probably not an actual oil pressure problem, more likely a bad reading. Do you know where the oil level sensor is located on your engine?

Thanks for the quick response! I haven't tried checking the connector myself yet, as I'm not entirely sure where to find the oil level sensor on this engine. Could you give me a general idea of where it's usually located? Also, if it is corroded, what's the best way to clean it?

It's usually on the lower part of the engine, near the oil pan. A quick Google search for "Peugeot 407 oil level sensor location" should give you a diagram. If it's corroded, disconnect the battery first, then use a wire brush and some electrical contact cleaner to clean the connector. But honestly, with those symptoms, and the mechanic already suspecting a connection issue, it might just be worth taking it to a shop. They can diagnose it properly. It will likely be the sensor, and if you want to change it yourself make sure you also drain the oil before doing so, so you don't make a mess.

Thanks a lot for the advice! I appreciate the tips on finding and cleaning the connector. I think, given the circumstances, I'll take it to the workshop as you suggested. They quoted me about 95€ to fix it. I'll let you know what they find!