P0700 means Transmission Control System Malfunction. The transmission control module has detected a fault and has asked the engine computer to turn on the check engine light. P0700 itself does not say what is wrong; the transmission module stores the specific code. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0700 means
Electronically controlled automatics are run by a transmission control module (TCM), a separate box or part of the engine computer. It reads speed sensors, the range sensor and fluid temperature to decide when to shift, and drives solenoids that apply clutches and the torque converter clutch. Many basic code readers only show the generic P0700; a scan tool that reads the transmission module shows the specific fault. Check fluid level and condition first, since low or burnt fluid causes many transmission codes.
P0700 symptoms
- Check engine light
- Harsh, late or erratic shifts
- Stuck in one gear or limp mode
Common causes of P0700
- Any transmission fault stored in the TCM: solenoids, speed sensors, range sensor, wiring or internal problems
- Low or burnt fluid
- TCM problems
How to diagnose P0700
- Use a scan tool that reads the transmission module to get the specific code
- Check fluid level and condition
- Diagnose the stored transmission code
Can you drive with P0700?
It depends on the underlying fault; if the transmission is in limp mode, drive only to a repair shop.
P0700 tips
Think of P0700 as a messenger: it says the transmission module has a fault stored, so real diagnosis starts with that transmission code. If your scan tool cannot read the transmission module, a shop with a fuller scanner can.
Will P0700 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0700 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0715 | Input/Turbine Speed Sensor A Circuit |
| P0720 | Output Speed Sensor Circuit |
| P0730 | Incorrect Gear Ratio |
| P0750 | Shift Solenoid A Malfunction |
Guides that help
- how to use an OBD2 scanner
- transmission won’t shift
- transmission control module
- transmission solenoid symptoms
- limp mode
- how to check transmission fluid
When it is more than a sensor
If the fault turns out to be internal (worn clutches, a failed converter or a damaged valve body), compare a rebuild with a replacement in transmission rebuild vs replacement and transmission replacement cost, identify your unit with what transmission do I have?, and browse our transmissions.
More guides: bad TCM symptoms.
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