P0704 means Clutch Switch Input Circuit. On manual-transmission vehicles, the computer is not seeing the expected signal from the clutch pedal switch. 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 P0704 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.
P0704 symptoms
- Engine will not crank on some vehicles
- Cruise control not working
- Check engine light
Common causes of P0704
- Misadjusted or failed clutch switch
- Wiring or connector fault
- Broken switch mounting
How to diagnose P0704
- Watch the clutch switch input on a scan tool while pressing the pedal
- Check switch adjustment
- Test the switch and wiring
Can you drive with P0704?
Usually yes, if the engine starts.
P0704 tips
Many manual cars will not crank unless the clutch switch closes, so a misadjusted switch can look like a starter problem.
Will P0704 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 P0704 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 |
|---|---|
| P0703 | Brake Switch B Input Circuit |
| P0700 | Transmission Control System Malfunction |
| P0705 | Transmission Range Sensor Circuit Malfunction (PRNDL Input) |
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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