Automotive Service Excellence (ASE) A8 Engine PerformanceFuel, Air Induction, and Exhaust Systems Diagnosis and RepairEasy
A customer complains of a strong gasoline odor near their vehicle, especially after refueling. Upon inspection, the technician notices a small crack in the EVAP purge line near the charcoal canister. Which of the following DTCs is MOST likely to be set due to this condition?
- AP0171 - System Too Lean (Bank 1)
- BP0420 - Catalyst System Efficiency Below Threshold (Bank 1)
- CP0442 - Evaporative Emission System Leak Detected (Small Leak)
- DP0301 - Cylinder 1 Misfire Detected
Show answer & explanationAnswer & explanation
Correct answer: C. P0442 - Evaporative Emission System Leak Detected (Small Leak)
A small crack in the EVAP purge line would allow fuel vapor to escape, which the EVAP system monitors for leaks. This fault is specifically designed to detect small leaks within the evaporative emission system.
Why the other options are wrong
- A. P0171 indicates a lean condition in the engine's air-fuel mixture, not directly an EVAP leak.
- B. P0420 relates to catalytic converter efficiency, not EVAP system leaks.
- D. P0301 indicates a misfire in cylinder 1, which is unrelated to an EVAP system leak.
EVAP Small Leak Detection
The Evaporative Emission Control System (EVAP) monitors for small leaks, typically indicated by DTC P0442, when fuel vapor escapes.
- Monitors for leaks in the fuel vapor recovery system.
- Small leaks can be caused by cracks in hoses or loose caps.
- DTC P0442 is common for small EVAP leaks.
Memory trick: EVAP leaks are like tiny gas ghosts escaping, triggering specific codes.