P0702 means Transmission Control System Electrical. The transmission control system has detected a general electrical fault, often in its power supply or internal circuits. 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 P0702 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.
P0702 symptoms
- Limp mode
- Harsh or no shifts
- Check engine light
Common causes of P0702
- Low battery voltage
- Poor power or ground to the transmission module
- Wiring or connector faults
- Module fault
How to diagnose P0702
- Check battery and charging voltage
- Check transmission module power and ground
- Read all transmission codes
Can you drive with P0702?
Only as needed; limp mode is meant to get you to a repair.
P0702 tips
Transmission electrical codes often follow a weak battery or corroded ground; repair the power supply and clear the code before deeper diagnosis.
Will P0702 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 P0702 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 |
|---|---|
| P0700 | Transmission Control System Malfunction |
| P0880 | TCM Power Input Signal |
| P0613 | TCM Processor |
Guides that help
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.
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