hac

Is there a HAC (High Altitude Compensation) circuit on these trucks? Or atmospheric pressure sensor? And if so, does anyone have a pic from the FSM that shows the components in the circuit? The issue is that above 9000 ft, the VSC and check engine lights come on, then go back off when I go to...

Here’s a basic question: When replacing vacuum lines on the HAC valve, the book references Left/Right for the various lines. Is this when the value is viewed from the top, or if looking straight at the ports? This makes a big difference in routing the lines.