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Nissan Maxima Check Engine Light: V6 & CVT Causes
Why a Nissan Maxima check engine light comes on — the 3.5 V6's P0420/P0430 converter codes, evap and sensor faults, and the CVT symptoms to watch for.
What it isA logged fault on the V6 Maxima — evap, sensor, converter, sometimes CVT
UrgencyModerate
Safe to drive?Steady and shifting smooth, yes. Blinking, shuddering, or limp mode, no
Typical cost$0 gas cap to ~$1,300 converter (V6 has two); CVT issues are a separate, larger cost
P0420P0430P0171P0455P0744
The Maxima is Nissan’s V6 sedan, and like the Murano it mixes two familiar ingredients: a V6 (more emissions plumbing) and a CVT (the transmission watch-item). So its check engine light can come from either direction, and the first job is figuring out which.
Engine-side, it’s routine V6: rule out the gas cap (a loose one sets an evap code), then look at oxygen sensors and the bank-specific converter codes P0420 (bank 1) and P0430 (bank 2). Two converters, more sensors — the code’s side tells you where to look, and neither automatically means a new converter, since an upstream sensor can set it.
Transmission-side, the Maxima’s CVT carries the usual caution. Shuddering, slipping, or limp mode along with the light points at the transmission, not a sensor — and that’s the one you address promptly, because CVT problems get pricier the longer they run. A steady light with smooth shifting is almost always an engine-side fault; a light with transmission symptoms is a different conversation. Before paying for CVT work, run your VIN — Nissan extended CVT coverage on some Maxima years. Rule out the cap, scan it, and pay attention to how the car is shifting, not just the light on the dash.
The move, step by step
- Tighten the gas cap — A loose-cap evap code is the cheapest, most common Maxima trigger. Free to rule out.
- Scan it — P0420/P0430 (converter, per bank) and oxygen-sensor codes are the V6 regulars.
- Note transmission behavior — A light with shuddering or limp mode points at the CVT, not a sensor.
- Check VIN for CVT coverage — Nissan extended CVT warranties on some model years — covered work can be free.
Tool for the job: a basic OBD2 scanner reads the exact code in under a minute. See scanners on Amazon →
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Nissan owners ask
What usually causes a check engine light on a Nissan Maxima?
The Maxima pairs a 3.5-liter V6 with a CVT, so it draws from both camps. On the engine side: a loose gas cap (evap code), oxygen sensors, and the bank-specific converter codes P0420 (bank 1) and P0430 (bank 2) as miles climb. On the transmission side: the CVT can trigger a light with shuddering or limp-mode symptoms. A steady light with smooth shifting is usually engine-side; a light with transmission symptoms points at the CVT. Scan it to be sure.
Does the Nissan Maxima have CVT issues behind the check engine light?
It can. The Maxima uses a continuously variable transmission, and like other Nissan CVTs, aging units can shudder, slip, overheat, or trigger limp mode, sometimes with a transmission code. A plain steady light is more often a sensor or converter fault, but a light alongside those driving symptoms points at the CVT. Nissan extended CVT coverage on certain model years, so check your VIN before paying for transmission work.
What do P0420 and P0430 mean on a Maxima?
They're catalytic-converter-efficiency codes for the two banks of the V6 — P0420 is bank 1, P0430 is bank 2. Each means that side's converter isn't cleaning the exhaust as expected. As with any P0420/P0430, a failing downstream oxygen sensor can trigger it, so diagnosis beats replacing a converter on a guess, particularly on a V6 where converters are expensive.
Is it safe to drive my Nissan Maxima with the check engine light on?
A steady light with the V6 running and shifting smoothly is generally fine to a scan within a few days. Stop driving it hard if the light is blinking (a misfire) or the Maxima is shuddering, slipping, or in limp mode — that points at the CVT, and those issues worsen the longer they run. A steady light with normal shifting is usually a routine engine-side fault.
Updated 2026-07-01 · Independent reference, not a substitute for a hands-on diagnosis.