P0704: Clutch Switch Input Circuit

What does P0704 mean?

Only on cars with a clutch pedal: the clutch switch tells the engine module that the clutch is depressed, used to cancel cruise control, smooth load changes when shifting and for stop-start. The check is a plausibility test over driving events rather than a voltage check: Saab's Trionic T8 expects a change of state every time the car pulls away from 3 to 50 km/h (four misses in a row), the EDC16 diesel at gear changes (25 in a row, above 35 km/h and 1500 rpm), and Ford compares its two clutch switches continuously. None of them lights the check engine light; cruise control is disabled. Separate clutch pedal switch codes are P0830–P0835.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Cruise control not working or not cancelling when declutching
• Jerks or rev hang when shifting
• Stop-start inactive
• Usually no check engine light

Common causes

• High Clutch switch faulty or misadjusted (does not switch or too late)
• Medium Connector or wiring at the pedal box damaged or corroded
• Medium Floor mat or pedal stop shifted, switch bracket broken
• Low Driving style (pulling away or shifting without fully depressing the clutch)

Likelihood is a general estimate across vehicles; your make and model may differ.