What does error code P10171-00 mean?

This particular error code denotes a lean running condition. That is, the engine either has too little fuel or too much air entering it. It's actually quite common on this engine and can be traced to several possible causes. Some of those include bad fuel injectors, a worn fuel pump, an intake vacuum leak, or – and this is where we'd look first on this engine – a bad PCV valve.

This valve is responsible for controlling the crankcase ventilation, but if it fails, it can allow the lean mixture condition to emerge which is when you'll get the error code and a check-engine light. The good news, is there's a quick and easy check if you know your way around an engine.

First, remove the plastic engine cover to reveal the rocker cover and the PCV valve. With the engine running, place a small piece of paper over the hole in the PCV valve. If the paper is drawn to the valve, you have a leaking PCV valve probably due to a broken diaphragm which is allowing extra air to enter the engine and create the lean mixture. If that doesn't work, make sure the oil cap is fitted tightly as a loose cap can cause the same problem. This certainly isn't the case for all engines, but experience has shown that in your car, it's a good place to start.

If the PCV valve theory doesn't work out, you're back to looking at things like fuel pressure, injector condition, intake tract leaks, a bad mass airflow meter or even a powertrain module fault.

The knocking noise could be anything from a poorly secured spare tyre to the struts that hold the boot or hatch in the raised position.