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Cabin Filters – ASE Practice Question (VIDEO)

Description Technician A says that cabin air filters protect the occupants from over 200 known contaminants found in a typical car’s passenger compartment. Technician B says that the cabin air filter protects the evaporator core from copper particles emitted by the...

Should You Replace That Damaged Plastic Intake Manifold?

It seems like plastic is everywhere under the hood of a modern car. You even have to remove a plastic cover to find the engine! But plastic and composite parts like distributor caps and ignition coil housings have been in use for over 100 years. In the 1970s,...

Politics Ain’t Politic

Red, blue, or green? You’ve pieced together the point of this article by now, no doubt. This will not be a piece that risks raising the hackles of those who are deeply political. That’s not because you’re encouraged to avoid the topic, but instead, to do what makes...

Belt Noise – ASE Practice Question (VIDEO)

Description Technician A says that "chirp" is the most common type of noise complaint customers bring to the shop. Technician B says that EPDM belts can be worn out yet pass a visual inspection. Who is correct?A) Technician AB) Technician BC) Both Technician A and BD)...

Diagnosing a Prius Coolant Leak (VIDEO)

Description When a Toyota Prius develops an exhaust leak or a coolant leak, the problems can be interrelated… and hard to diagnose. Dorman Training Center instructor Vince Manship explains the functions and failures of the Prius heat exchanger system.Related Videos

A Crash Course on Modern Impact Sensors

We’ve come a long way since the automotive impact detector was developed decades ago. One clever design used a metal ball in a tube that would move to complete a circuit during a collision. This rudimentary accelerometer proved that the idea of detecting a collision...

Cat DTC Diagnosis (P0420) – ASE Practice Question (VIDEO)

by | May 26, 2026

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Description

Technician A and Technician B are discussing the troubleshooting procedure for a P0420 (Catalyst Efficiency Below Threshold) DTC. Technician A says that the presence of any other codes should be considered first before replacing the converter. Technician B says that an air leak in the exhaust upstream from the converter could cause the code to set.

Who is correct?
A) Technician A
B) Technician B
C) Both Technician A and B
D) Neither Technician A or B

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