P0704
Clutch Switch Input Circuit.
- Generic
- Powertrain
- Generic code
- Low severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- 04
- FaultThe specific fault in that area
What it means
P0704 is the generic code for a fault in the clutch switch input circuit. The engine or transmission control unit monitors the signal from the clutch pedal switch and sets this code when the signal is missing, stuck, out of range or does not make sense compared with other data such as vehicle speed, engine speed and gear selection. The exact switch design and how many switches are fitted vary by model.
Symptoms
- Malfunction indicator lamp on
- Engine will not crank, or cranks only when the clutch is pressed hard or the pedal is held at a certain position
- Cruise control not working or cancelling unexpectedly
- Stop-start system not working or behaving erratically
- Hesitation, surging or poor throttle response when changing gear on some models
- Clutch pedal feels normal but the control unit seems unaware of its position
Possible causes
- Faulty or misadjusted clutch pedal switchlikely
- Damaged wiring, chafed loom or poor connection at the switch connectorlikely
- Corroded or contaminated switch connector terminalspossible
- Clutch pedal bracket, striker or plunger worn, bent or out of positionpossible
- Blown fuse or fault in the supply or ground to the switch circuitpossible
- Fault inside the control unit processing the switch inputrare
- Outdated control unit software where the manufacturer has issued a correction for switch plausibilityrare
How to diagnose
- Read all stored and pending codes and note the freeze frame data, including whether any other clutch, gear or speed related codes are present
- Check the clutch switch operation visually: with the pedal pressed and released, confirm the plunger or striker contacts the switch and moves freely
- Inspect the switch connector and wiring for damage, water ingress, corrosion and pin tension
- Check the relevant fuse and the supply and ground to the switch against the wiring diagram
- Using a scan tool live data, watch the clutch switch status change as the pedal is pressed and released, and check it matches the pedal position
- Measure the switch with a multimeter for continuity and resistance in both pedal positions, following the manufacturer's specification
- Check the wiring between the switch and control unit for open circuit, short to ground or short to supply
- Check whether the manufacturer has issued a software update or technical bulletin for this model and engine
How to fix
- Adjust or replace the clutch pedal switch as required
- Repair or replace damaged wiring and connectors, cleaning or renewing corroded terminals
- Repair or replace a worn pedal bracket, striker or plunger so the switch is actuated correctly
- Restore the fuse, supply or ground fault found in the switch circuit
- Update the control unit software only if a manufacturer-approved update addresses this fault
- Replace or repair the control unit only after all wiring and switch checks have been passed
Can I keep driving?
Low severity
The car can usually be driven, but starting problems or loss of cruise control and stop-start may occur. Get it checked soon, particularly if it sometimes fails to start, as you could be left stranded.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.