Engine Performance (A8)Question 103 of 120
A loose or missing fuel cap most commonly sets which type of code?
a.An EVAP system leak code (such as P0455 or P0457)
b.A misfire code
c.A coolant temperature code
d.An ABS code
Explanation
A poorly sealing fuel cap lets vapors escape and triggers an EVAP leak code, often the first thing to check for such faults. Tightening or replacing the cap and clearing the code frequently resolves it. Smoke testing finds larger leaks in the system.
Practice all 120 questions free — no signup required.
Related questions on this topic
- In a modern coil-on-plug ignition system, each coil:
- A knock sensor allows the PCM to:
- The EVAP system is designed to:
- Technician A says low fuel pressure can cause a lean misfire and hesitation. Technician B says a clogged fuel filter or weak pump can lower fuel pressure. Who is correct?
- The throttle position sensor (TPS) informs the PCM about:
- A vehicle fails an emissions test for high hydrocarbons (HC). This is most commonly associated with:
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against ASE Automobile Certification Series (A1–A8) · How we review