Electrical Systems & Emissions Control Flashcards
7 cards from real NAPA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Electrical Systems & Emissions Control flashcards as text
A replacement fuse blows immediately when the circuit is switched on. What is the most likely cause?
Answer: A short to ground in the circuit
A short to ground bypasses the load, causing excessive current that instantly opens the fuse.
What is the purpose of a secondary air injection system?
Answer: Pump fresh air into the exhaust during cold start to help heat the catalyst
Added oxygen in the exhaust burns HC and CO and speeds catalyst warm-up after a cold start.
What happens to OBD II readiness monitors after DTCs are cleared with a scan tool?
Answer: They reset to incomplete until drive cycles are completed
Clearing codes resets monitors to not ready, which can cause an emissions inspection rejection until they run.
A three-way catalytic converter works most efficiently at which air-fuel ratio?
Answer: About 14.7:1
At stoichiometric 14.7:1, the catalyst can simultaneously oxidize HC and CO and reduce NOx.
What color is used to identify high-voltage cables on hybrid and electric vehicles?
Answer: Orange
Industry practice uses orange insulation to mark high-voltage cables that require special safety precautions.
A vehicle's battery goes dead after sitting for two days. What test should be performed first after confirming the battery and charging system are good?
Answer: A parasitic draw test
A healthy battery that drains while parked points to an excessive key-off current draw.
Which pollutant is mainly reduced by the reduction section of a three-way catalytic converter?
Answer: NOx
The reduction catalyst, typically rhodium, strips oxygen from NOx to form nitrogen and oxygen.