P0733 Fault Code in Audi: Causes, Symptoms, and Fixes

The P0733 fault code indicates that the Transmission Control Module (TCM) has detected an incorrect gear ratio while the vehicle is in 3rd gear. This usually means the actual speed of the output shaft doesn’t match the expected speed for 3rd gear, suggesting a mechanical or hydraulic issue inside the transmission.

Common Symptoms:

1. Check Engine Light (CEL)
2. Harsh or delayed shifting (especially into or out of 3rd gear)
3.️ Transmission slipping
4. Poor acceleration
5. Transmission stuck in limp mode

6.️ Reduced fuel economy

Common Causes:

1. Worn or slipping clutch pack (3rd gear clutch inside transmission)
2. Low or dirty transmission fluid
3. Faulty transmission solenoid
4. Damaged valve body
5. Internal transmission failure
6. Faulty speed sensors (input/output)
7. Incorrect transmission fluid used

️ How to Fix It:

✅ Step-by-step Diagnosis:
1. Check transmission fluid
– Level should be correct, and fluid should be clean and red—not burnt or dark.
2. Scan with a professional tool
– Check live gear ratios, shift timing, and solenoid function
– Look for companion codes like P0720, P0715, P0741
3. Inspect speed sensors
– A bad input/output speed sensor can misreport gear speeds
4. Test solenoids and valve body (if accessible)
5. Replace if stuck or electrically faulty
– Perform a pressure test (if slipping is suspected)
– Confirms if clutches are engaging correctly
– Transmission rebuild/replacement (if internal failure is confirmed)

Found In:

1. DSG, CVT, and ZF transmissions
2. Common on Audi, VW, BMW, Hyundai, Ford, Toyota, Mercedes-Benz, etc.