P0704 Fault Code in Audi: Causes, Symptoms, and Fixes

The P0704 fault code** indicates that the Engine Control Module (ECM) or Transmission Control Module (TCM) has detected an issue with the clutch switch input circuit.
This applies mainly to manual transmission vehicles, or automatic vehicles that use a clutch switch for start/stop systems or gear logic.

Common Symptoms:

1. Check Engine Light (CEL)
2. Cruise control not working
3. Car won’t start (especially in manual)
4. Transmission may not shift as expected
5. ECM may not receive correct input for clutch engagement

Common Causes:

1. Faulty clutch pedal switch
2. Worn clutch switch wiring or connector
3. Stuck or misadjusted clutch pedal sensor
4. Corroded or loose ground connection
5. Faulty TCM/ECM (rare)

How to Fix It:

✅ Step-by-step:
1. Inspect the clutch pedal switch
– Usually located near the clutch pedal arm
– Listen for a click when pedal is pressed; if no sound, it may be stuck or broken
2. Test the switch with a multimeter
– Should show continuity when pedal is pressed
3. Check wiring and connector
– Look for loose pins, corrosion, or broken wires
4. Replace the clutch switch if faulty (usually an inexpensive part)
5. Clear code and retest

Applies To:

1. Manual transmission cars (BMW, VW, Audi, Ford, Toyota, etc.)
2. Some automatics with smart start/stop features