P0700: Transmission Control System Malfunction
P0700 is an informational "generic" code meaning the transmission control module (TCM) logged a fault and lit the check engine light — but it does not name the fault itself; you must read the sub-code.
What it means exactly
P0700 only tells you "there is a transmission problem." The actual fault is stored as another transmission code (e.g. P0730/P0741…) that you read with a scanner supporting transmission codes.
How to find the real cause
Use an OBD2 that reads transmission codes (not just engine). The sub-code names the issue: gear ratio, torque-converter clutch, a solenoid…
Common causes
Degraded/low transmission fluid, a speed sensor, a solenoid pack, or an electrical issue. Start by checking transmission fluid and its level.
FAQ
Can I drive with P0700?
If the transmission behaves normally, cautiously and briefly — but read the sub-code soon; the transmission may degrade.
Why no fault detail?
Because P0700 is just a general flag from the transmission to the engine; the detail is in the transmission sub-code.