2021 Nissan Sentra Check Engine Light Codes

The most common diagnostic trouble codes for a 2021 Nissan Sentra include P0420 (catalyst system efficiency), P0442 (evaporative system small leak), P0135 (oxygen sensor heater circuit), and P0300 (random/multiple cylinder misfire). Left unaddressed, P0420 can cause reduced fuel economy and premature catalytic converter failure—leading to repair costs that far exceed a timely diagnosis. A P0442 leak can trigger emissions failures and decreased fuel vapor containment, while an oxygen sensor fault (P0135) causes poor combustion control and increased fuel use. Ignoring misfires (P0300) risks internal engine damage. At Larry H. Miller Nissan Mesa in Mesa, AZ, we interpret these codes in context—examining live data, conducting smoke or pressure tests, and recommending repairs that restore performance. Our certified technicians use Nissan OEM parts to maintain warranty compliance and vehicle longevity. We also offer transparent pricing, available service specials, and flexible service financing so you can complete needed work immediately and save long-term on fuel and repairs. For dependable, factory-level diagnostics, schedule service with us today.

Check Engine Light Flashing

A flashing check engine light on a 2021 Nissan Sentra typically indicates a severe misfire that can overheat the catalytic converter and cause rapid engine damage. This is an urgent condition—do not continue driving if the light is flashing. Bring your vehicle to Larry H. Miller Nissan Mesa immediately so our technicians can minimize damage and cost. We triage flashing-light vehicles promptly, perform a safe tow if necessary, and diagnose root causes using OEM-level tools. We also review any available service specials or loyalty program benefits and explain warranty coverage—as a certified dealer we ensure warranty repairs are performed correctly. Our team makes it easy to schedule service online and offers service financing to get you back on the road with confidence.

2021 Nissan Sentra Check Engine Light Reset

Resetting a check engine light on a 2021 Nissan Sentra is simple when performed by professionals: we clear active codes only after verifying repairs and confirming the underlying issue is fixed. DIY resets without repair can mask problems and lead to repeated failures or warranty complications. At Larry H. Miller Nissan Mesa, our approach is transparent—diagnose, repair with OEM parts, then clear codes and perform road tests to confirm resolution. This method protects your vehicle’s systems and preserves warranty integrity; any warranty-covered repairs must be done at a certified dealership. We provide clear estimates, apply available service specials, and offer financing so you can address repairs now and pay later. To ensure a lasting fix and accurate code reset, schedule service with our Nissan specialists in Mesa.