Drivers are often surprised that a transmission code can fail a smog check. It makes sense once you see how Nevada's test works: the analyzer reads the vehicle's OBD II computer and fails any light-duty 1996 or newer vehicle whose check engine light is on. P0700 is the transmission's way of switching that lamp on.
At a glance
- SAE J2012 meaning: Transmission control system malfunction (MIL request).
- MIL is the malfunction indicator lamp, the check engine light.
- Nevada's rule is about the lamp: lit means fail, whichever module requested it (DMV).
- P0700 is a pointer: the detailed transmission code is stored in the transmission module.
A request, not a diagnosis
The SAE J2012 definition reads "Transmission control system malfunction (MIL request)." MIL stands for malfunction indicator lamp, the light you know as Check Engine or Service Engine Soon. On many vehicles the transmission has its own computer. When it detects a fault, it stores a detailed code of its own and sends a request to the engine computer to light the lamp. The engine computer records that request as P0700.
So P0700 tells you which system raised the flag, and almost nothing about what is wrong. A repair shop reads the transmission module separately to find the specific code.
Why a transmission code matters to the smog test
Nevada's OBD II inspection does not sort codes by system. The Nevada DMV's rule is simply that a check engine light that is on is an automatic fail for a 1996 or newer light-duty vehicle. The test is about the lamp, not about the transmission. A car that shifts perfectly but carries a stored P0700 with the lamp lit still fails, and a car with a transmission complaint but no lit lamp is judged on the rest of its OBD data.
There is also a practical link. Transmission behavior affects engine load and speed, and the vehicle's computers share information, so manufacturers treat some transmission faults as emissions-relevant. That is the reason the lamp request exists.
Common causes a repair shop checks
Because P0700 is only the request, common causes a repair shop checks start with reading the transmission module's own code. From there, typical areas include shift solenoids and their wiring, transmission speed or range sensors, fluid level and condition, and connector or communication faults between the modules. The shop decides what the repair is.
If the transmission feels wrong
Some transmission faults put the vehicle in a fallback mode, often called limp mode, where it holds one gear. If the vehicle is shifting harshly or not shifting, get it to a repair shop before worrying about the smog check. If the check engine light is flashing, the DMV's advice is to slow down or stop driving and get service right away, because a flashing lamp signals a severe malfunction.
Testing with P0700 stored
If the vehicle drives safely, testing before the repair has benefits the DMV spells out. The failed report documents why the vehicle failed, allows a ten-day movement permit at reduced cost if registration has expired, and starts the waiver process. Repair money spent before that first failed test does not count toward a waiver.
Do not clear codes or disconnect the battery to hide the light before the test. The DMV says that gets the vehicle rejected as not ready, followed by up to a week of driving before it can be tested.
The waiver path in Washoe
A waiver is possible when a 1996 or newer light-duty vehicle still fails for a lit check engine lamp after repairs. In Washoe County the DMV asks for receipts showing at least $200 in parts and labor at a 2G licensed authorized station for repairs directly related to the failure, or at least $200 in related parts bought by the owner within 14 days after the initial test. Then the vehicle, both failed certificates and all receipts go to the DMV Emission Lab. See the waiver page.
Ask the dealer first about a recall or the federal emissions warranty. Federal law covers some expensive emission components for up to 8 years or 80,000 miles; whether a transmission part qualifies depends on the vehicle, and the dealer can check by VIN.
Sources
- dmv.nv.gov/emission_obd.htm (Nevada DMV OBD page: a lit check engine light is an automatic fail, flashing light, test anyway, cleared codes, emissions warranty; read 11/3/26)
- dmv.nv.gov/regrenewal.htm (Nevada DMV: failed test, repair and Washoe waiver receipts; read 11/3/26)
- epa.gov/state-and-local-transportation/vehicle-emissions-inspection-and-maintenance-im-inf (EPA: state inspection and maintenance programs, Nevada included; read 11/3/26)
- obd-codes.com/p0700 (public code reference for the P0700 definition; read 11/3/26)
