Transmission Control System Malfunction

P0700 is a generic transmission code -- you need to pull the specific trans codes (P07xx) with a scanner. On Chrysler/Dodge, the most common root cause is the transmission output speed sensor (Mopar 4800878) or solenoid pack failure. Check the ATF fluid condition first -- dark or burnt fluid indicates internal damage.

P0700 on GM vehicles often accompanies P0717 or P0776. The 6T40/6T45 transmission has a known issue with wave plate failure causing a hard 1-2 shift. GM TSB #18-NA-025. Check for trans codes first. If the trans is slipping, a rebuild may be needed. Fluid change with ACDelco Dexron VI is a good first step if fluid is dark.

P0700 on Nissan CVT transmissions is a red flag for CVT failure. Nissan JATCO CVT units are known to fail around 80-120K miles. Check for shuddering and whining. Nissan extended the CVT warranty to 10 years/120K on some models. Check with the dealer before paying out of pocket. A CVT fluid drain and fill can buy time -- use the genuine Nissan fluid your year specifies (NS-2 on earlier units, NS-3 from roughly the early 2010s).

P0700 on Honda often points to the transmission range switch (Neutral safety switch) or a failed torque converter lockup solenoid. Pull the specific sub-codes first. CHECK WHICH TRANSMISSION YOU HAVE BEFORE BUYING FLUID: conventional Honda automatics take ATF-DW1, but Honda CVTs (most Civic from 2014, Accord from 2013, plus HR-V and Fit) require HCF-2 instead, and DW-1 will damage a CVT. Neither is interchangeable with generic Dexron. On a conventional automatic, a fluid drain and fill (3x3 method) often resolves early shift problems.