Hello, thank you for choosing Just Answer. My name is XXXXX XXXXX X will help you sort out your various trouble codes.

First, let's define the codes:
P0326 - Indicates a fault with your knock sensor.
P0075 - Indicates a fault with your intake valve control solenoid.
P0446 & P0458 - Both indicate a fault with your evaporative emissions system.

When you have multiple codes like this, your best bet is to have a reputable independent shop sort things out.

Without the benefit of seeing the car, I suspect you have two separate problems causing the four codes.

I would bet that P0326, the knock sensor out of range code, is being caused by P0075. If the intake valve control solenoid cannot adjust camshaft timing appropriately, this can cause a knock in the engine. I would look there first.

The P0446 and P0458 indicate a problem with the purge solenoid or a leaky evaporative emissions system. I would bet a dollar against a doughnut that the same failure is causing both codes. Sometimes this is as simple as a faulty gas cap. However the S60s are plagued with evaporative emission problems that stem from faulty valves and/or failed vacuum lines.

As I indicated initially, proper diagnosis will require an experienced Volvo mechanic and due diligence. I would stay away from the dealer as they tend to replace parts first and diagnose later.

Let me know if you have any additional questions. Please don't forget to click accept. The website is paid from your deposit either way, but I am only compensated for accepted answers. I am always happy to offer additional help when necessary.

Best Regards,
Stephen