Gear 2 Incorrect ratio
Your transmission isn't shifting into 2nd gear correctly—the engine speed and vehicle speed don't match what the computer expects. It's like trying to pedal a bicycle in the wrong gear, causing inefficient power delivery.
The ECM monitors the ratio between engine RPM and output shaft speed during 2nd gear engagement using data from transmission speed sensors. If the calculated gear ratio deviates from the expected range, it indicates slippage, sensor failure, or internal transmission wear. The ECU compares actual vs. theoretical RPM ratios to detect mechanical or hydraulic problems.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| 2nd Gear Ratio | Within 5% of expected ratio | Exceeds 10% deviation or outside acceptable band |
| Transmission Fluid Pressure | 200-350 PSI during 2nd gear | Below 150 PSI indicating low pressure or slipping |
Code P0733 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0733 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.