Core Concepts and Principles Flashcards

In a VW TSI engine, where does the high-pressure fuel system mainly deliver fuel?

Answer: Directly into the combustion chamber

TSI engines use gasoline direct injection, spraying fuel at high pressure straight into the cylinder.

What happens during regeneration of a diesel particulate filter (DPF) on a VW TDI?

Answer: Accumulated soot is burned off at high exhaust temperature

Regeneration raises exhaust temperature to oxidize trapped soot into CO2.

What is the purpose of the AdBlue (DEF) system on VW SCR-equipped diesel vehicles?

Answer: To reduce NOx emissions by injecting a urea solution into the exhaust

Selective catalytic reduction uses urea-based fluid to convert NOx into nitrogen and water.

In a parallel circuit, how does total resistance compare with the individual branch resistances?

Answer: It is always less than the smallest branch resistance

Adding parallel branches creates more current paths, so total resistance falls below the smallest branch value.

A VW repair manual specifies 100 Nm for a fastener. Approximately what is that in ft-lb?

Answer: 74 ft-lb

1 Nm equals about 0.738 ft-lb, so 100 Nm is about 74 ft-lb.

What does the generic OBD-II code P0300 indicate?

Answer: Random/multiple cylinder misfire detected

P0300 indicates random or multiple misfires, while P0301-P0306 point to specific cylinders.

What does freeze frame data stored with a DTC provide?

Answer: A snapshot of operating conditions at the moment the fault was set

Freeze frame records values such as RPM, load, coolant temperature, and speed when the fault code was stored.