P2191 means that under higher engine load the mixture goes too lean on bank 1 — the engine is getting more air than fuel for the demand. On the Accent the usual suspects are an unmetered air (vacuum) leak, a weak fuel-delivery component, or a dirty/incorrect air-mass reading. Diagnose it with fuel-trim data at load rather than throwing parts at it.
What the real-world data shows
Owner complaints: NHTSA lists 1 recall and 80 owner complaints for the 2014 Accent overall (pulled 2026-10-04); of those, about a dozen describe lean-type driveability symptoms (hesitation, rough running, stalling). Treat that as context, not a diagnosis — but do check your VIN for the open recall.
How often this is searched: P2191 on the Accent appears in our first-party Bing search logs, which is why we built this page.
Common causes on the Hyundai Accent
- Unmetered-air (vacuum) leak — cracked intake hose, PCV, or a leaking intake/gasket — that leans the mixture most under load
- Weak fuel delivery: failing fuel pump, restricted filter/sock, or low fuel pressure that cannot keep up at higher demand
- Dirty or failing mass air flow (MAF) sensor under-reporting airflow
- Clogged or weak fuel injectors
- Exhaust leak ahead of the upstream oxygen sensor skewing the mixture reading
How to diagnose it
- Read fuel trims at load — Watch short- and long-term fuel trim in live data. Trims that climb strongly positive as load increases confirm a genuine lean-at-load condition and tell you the ECM is already adding fuel to compensate.
- Smoke-test for vacuum leaks — A vacuum/intake leak is the most common and cheapest cause. Smoke-test the intake, check the PCV and all hoses before touching fuel components.
- Check fuel pressure/delivery under load — If trims spike only under load, test fuel pressure during a load/acceleration and inspect the filter/pump. Lean-only-under-load strongly implicates fuel delivery.
- Inspect the MAF and for exhaust leaks — Clean or test the MAF, and check for a pre-O2 exhaust leak that can trick the system into reading lean. Repair the root cause, clear, and re-drive to confirm trims return to normal.
What the fix costs
Typical range: $0–$700 (US). Hugely cause-dependent: a vacuum hose or cleaning the MAF can be near-zero, a fuel pump is often $300–700 installed, and injectors vary. Diagnose first — the code itself names no single part.
FAQ
What is the difference between P2191 and P0171?
Both are "too lean" on bank 1, but P0171 is lean in general while P2191 is specifically lean at higher load. That load-dependence is a clue: it points more toward fuel-delivery that cannot keep up under demand, or a leak that matters most when airflow is high.
Is it safe to drive with P2191?
Short-term and gently, yes, but a persistently lean mixture under load can cause hesitation and, over time, run the engine hotter than ideal. Diagnose it promptly rather than ignoring it.
Could it just be a vacuum leak?
Very often, yes — an unmetered-air leak is the single most common cause and the cheapest to fix. That is why a smoke test comes before any fuel-system parts.
How we researched this
Recall/complaint totals were retrieved 2026-10-04 from NHTSA’s public APIs for the Hyundai Accent and are vehicle-level. The lean-symptom tally is a rough keyword review of those complaints, offered as context only. Causes, diagnostic order and cost ranges are restated general service facts. No fabricated statistics are used.
Sources: NHTSA recalls & complaints (Hyundai Accent); SAE J2012 DTC definition (P2191 — System Too Lean at Higher Load, Bank 1); AutoDTCs first-party Bing Webmaster search-demand logs
Last updated 2026-10-04.