Holden SUV Range

This is possibly a very simple problem, caused either by the sensor (or switch) that detects the brakes have been applied, or a blown fuse that protects this electrical circuit. You could also have a broken wire somewhere within the loom, or even a problem with the body computer that controls many of a modern car’s functions. But start with the simple stuff first.

If the problem is an intermittent one, we’d definitely start looking at the switch that links the brake pedal to the brake lights.

Here’s how the owner’s manual describes the process:

• Press the Menu button on the steering wheel (or the indictor stalk depending on your car).
• Scroll down to the Toolbox or Settings icon.
• Press and hold the Enter or Set/Reset button.
• Hit the Language icon and press Enter.
• Select English and press Enter again.

That should do the trick, but you can also switch from Korean to English from the infotainment screen via the same process, starting with the Settings menu.

Fault code PO171 usually indicates a lean air:fuel mixture entering the engine. As in there’s too much air and not enough fuel. This creates all sort of problems including poor running, but it could also lead to engine damage in the longer term.

Experience suggests that in this particular engine, this problem is often caused by a vacuum leak, and, in turn, that’s often caused by the PCV (positive crankcase ventilation). Since you’ve changed your PCV (presumably for a band-new one) that probably rules that out, but it would still be worth a check. After that, you need to start looking for leaks in the various vacuum hoses around the engine, and don’t forget to make sure that the dipstick and the oil filler car are both sealing, as these can lead to vacuum leaks, too.

If none of that identifies the problem, you may need to check and clean the air flow sensor. If this is giving false readings, the mixture will be wrong as the engine’s computer is getting poor quality information.

But before any of that, did you reset the check engine light after performing the repairs you’ve mentioned? It could be that simple.