--- title: P0174 and Your Nevada Smog Check | Xpress Smog Check Center url: https://xpresssmogcenter.com/codes/p0174/ business: Xpress Smog Check Center (Located inside Xpress Oil & Lube Center) locations: Reno Northwest: 6100 Mae Anne Ave, Reno, NV 89523, (775) 787-1000, Mon-Fri 8 am-5 pm, Sat 8 am-4 pm, Sun closed; Reno South: 4993 Longley Ln, Reno, NV 89502, (775) 828-6996, Mon-Fri 8 am-5 pm, Sat 8 am-3 pm, Sun closed type: Nevada smog check (vehicle emissions inspection), drive in, no appointment --- Located inside Xpress Oil & Lube Center - Smog check at two Reno locations - Oil change in the same visit - No appointment needed [Xpress Oil & Lube](https://xpressoilandlube.com/) - [Home](https://xpresssmogcenter.com/) - [Codes](https://xpresssmogcenter.com/codes/) - P0174 # P0174 and your Nevada smog check P0174 is set when the second bank of a V6 or V8 engine is running lean and the computer cannot add enough fuel to correct it. Like any code that lights the check engine lamp, it fails a 1996 or newer light-duty vehicle at the Nevada OBD smog check. 4.7 stars from 550 Google reviews of the two Reno Xpress Oil & Lube Centers P0174 rarely travels alone. On many V engines it shows up together with P0171, the same lean condition on the other bank, and that pairing is a clue in itself. This page sets out what the code means, why the pairing matters to whoever repairs the car, and how the smog rules treat it in Washoe County. ## At a glance - SAE J2012 wording for P0174: System too lean (bank 2). - Seen together with P0171, it suggests a cause both sides of the engine share. - A lean code with the lamp lit fails the Nevada OBD test for 1996 and newer light-duty vehicles. - Test early: a pass is good for 90 days, so early testing leaves room for repairs. ## Two banks, one computer A V engine has two rows of cylinders, each with its own exhaust path and front oxygen sensor. The computer keeps a separate fuel correction for each. SAE J2012 gives each bank its own lean code, and the one for the side without cylinder 1 is P0174: System too lean (bank 2). The code means bank 2 kept reporting extra oxygen in the exhaust and the computer ran out of room to add fuel. Bank 1 has the matching code [P0171](https://xpresssmogcenter.com/codes/p0171/). The opposite condition, too much fuel, is [P0172](https://xpresssmogcenter.com/codes/p0172/) on bank 1. ## Both banks or just one When only bank 2 is lean, a repair shop tends to look at things that belong to that side alone. When both P0171 and P0174 are stored, the more likely suspects are things both banks share, like the air flow measurement or the fuel supply. That is a general pattern, not a diagnosis, and a repair shop will confirm it on your vehicle. Either way, tell the repair shop every code that was stored, not only the one that sent you there. A list of two or three codes together often says more about the cause than any single code does, and it saves time spent chasing the wrong side of the engine. ## How the test treats a lean code The Nevada OBD inspection does not weigh one code against another. If the check engine lamp is on, a 1996 or newer car or light truck fails, and the technician's analyzer sends that result to the DMV. That failed result is worth having. The DMV calls it a legal document showing why the vehicle fails, and it is required before repair receipts can count toward a waiver. It also lets you request a challenge test at the emissions lab. ## Common causes a repair shop checks We test; a repair shop finds and fixes the fault, and the DMV recommends a 2G licensed authorized station for emissions work. Common causes a repair shop checks include: - Unmetered air entering through a vacuum leak or intake gasket on bank 2. - Air flow sensor readings that run low, especially when both banks are lean. - Fuel pressure or delivery that falls short under load. - Exhaust leaks near the bank 2 front oxygen sensor. ## Getting from code to pass Plan backward from your registration date. - Test early in the renewal window. A passing test is valid for 90 days, and the DMV suggests early testing so there is time for repairs. - With a failed report in hand, get the repair done and keep every receipt. - Ask the dealer first about federal emissions warranty coverage or a recall if an expensive emission component is involved; federal law covers some for up to 8 years or 80,000 miles. - Do not clear codes right before the retest. After a repair, drive up to a week under varying conditions so the self-checks finish. ## The Washoe waiver, briefly If the lamp is still lit after repairs, a 1996 or newer light-duty vehicle may qualify for a waiver. Washoe County asks for receipts of at least $200 in parts and labor for related repairs by a 2G station, or at least $200 in related parts bought by the owner within 14 days of the initial test. Take the vehicle, both failed certificates and the receipts to the DMV Emission Lab; the DMV does not charge for the waiver, which lasts one year. ### Sources - [dmv.nv.gov/emission_obd.htm](https://dmv.nv.gov/emission_obd.htm) (Nevada DMV OBD page: lamp on is a fail, failed test is a legal document, challenge test, test early, renewing after a pass; read 11/3/26) - [dmv.nv.gov/regrenewal.htm](https://dmv.nv.gov/regrenewal.htm) (Nevada DMV renewal page: Washoe waiver receipts, $200 minimum, no charge, valid one year; read 11/3/26) - [obd-codes.com/p0174](https://www.obd-codes.com/p0174) (public OBD II code reference: P0174 system too lean, bank 2; read 11/3/26) ### P0174, the generic definition System too lean (bank 2) The SAE J2012 code title. The same P0 code means the same thing on every 1996 and newer OBD II vehicle; the cause behind it differs car to car. ### Your location: Reno South - Call [(775) 828-6996](tel:+17758286996) Mon-Fri 8 am-5 pm, Sat 8 am-3 pm, Sun closed - Address 4993 Longley Ln, Reno, NV 89502 [Directions](https://www.google.com/maps/dir/?api=1&destination=4993+Longley+Ln%2C+Reno%2C+NV+89502&destination_place_id=ChIJc5xNCcI_mYARXjHn3y79iJw) ### Related - [Check engine codes](https://xpresssmogcenter.com/codes/) - [P0171 and your Nevada smog check](https://xpresssmogcenter.com/codes/p0171/) - [P0172 and your Nevada smog check](https://xpresssmogcenter.com/codes/p0172/) - [Repair and retest](https://xpresssmogcenter.com/smog-check/repair-and-retest/) - [Smog waiver in Washoe County](https://xpresssmogcenter.com/smog-check/smog-waiver/) Located inside Xpress Oil & Lube Center Both smog check locations sit inside an Xpress Oil & Lube Center, the locally owned Reno drive-in that has served this town since 1983. Drive in, no appointment; get your oil changed in the same visit. [About us](https://xpresssmogcenter.com/about/) ## More fuel mixture codes [P0171 System too lean (bank 1) Learn more](https://xpresssmogcenter.com/codes/p0171/)[P0172 System too rich (bank 1) Learn more](https://xpresssmogcenter.com/codes/p0172/) ## If the light is on at your smog check [### Check engine light and your smog check Why a lit check engine light decides the test. Learn more](https://xpresssmogcenter.com/smog-check/check-engine-light/)[### Failed a smog check What the failed report means and the steps that follow. Learn more](https://xpresssmogcenter.com/smog-check/failed-smog-check/)[### Repair and retest Getting the repair done and coming back for the second test. Learn more](https://xpresssmogcenter.com/smog-check/repair-and-retest/)[### Rejected: not ready to test Why a car can be turned away without failing. Learn more](https://xpresssmogcenter.com/smog-check/not-ready-rejected/) ## P0174 questions Still have a question? Call either Reno location or just drive in; there is no appointment to make. ### Why do P0171 and P0174 often show up together? Because some causes affect the air or fuel for the whole engine. A repair shop uses the pairing as a starting point. ### My truck has a four-cylinder engine and shows P0174. Is that possible? Bank 2 codes belong to engines with two banks. If you see one on a single-bank engine, have a repair shop confirm the code and the scan tool reading. ### Can I renew online after the retest passes? Yes. The DMV says you can renew online, at a DMV Now kiosk or at a station that offers renewal soon after a passing test, since results go to the DMV electronically.