Peugeot 307 VANOS Solenoid Issue

I had a similar issue on my 307 (also diesel!). Check engine light and fuel economy went bad. I'm no expert, but it felt like I was driving with the handbrake on! Notice any loss of power, especially at lower revs? If so, it's probably the variable timing. I'd check those VANOS solenoids first. Easy enough to get to, but be careful with the electrical connectors; they can be brittle. Also, have you checked your timing chain?

Thanks for the tip! There's definitely a noticeable drop in power, especially when accelerating. When you say 'check the solenoids', what exactly did you do? Did you test them somehow, or just replace them? Also, where exactly are they located?

Low power is a dead giveaway. I'm no mechanic. I tried fiddling about with it but ended up making a mess. I booked it into the local workshop and they hooked it up to diagnostics. It turned out to be a faulty VANOS solenoid. They replaced it, cleared the codes, and it was back to normal. You could try testing them yourself with a multimeter, but unless you're confident, I'd say get it checked professionally. Saved me a lot of hassle. The garage said that a defect in one of the camshaft solenoid valves or power supply was the cause.

Appreciate the advice. Took it to a garage, and you were spot on – faulty VANOS solenoid. Replaced it, and the car's running much better now. Cost me about 250€ all in. Thanks again for pointing me in the right direction!