Hello, thank you for choosing Just Answer. My name is XXXXX XXXXX I 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.
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