Gear 3 Incorrect Ratio
The Powertrain Control Module (PCM) has detected that the transmission is not shifting into or maintaining the correct gear ratio for third gear. It sets this code when the input RPM and output RPM of the transmission do not match the expected mathematical ratio for gear 3.
Transmission ratio codes indicate a significant drivability issue that can lead to further internal transmission damage if ignored. The vehicle may go into limp mode, making it unsafe for highway driving.
Common symptoms
- Check Engine Light illuminated
- Transmission slipping when shifting into or driving in third gear
- Delayed or harsh shifting into third gear
- Vehicle goes into limp mode (failsafe mode) restricting gears
- Decreased fuel economy and poor acceleration
Likely causes
- Low or dirty transmission fluid
- Defective shift solenoid responsible for third gear
- Worn clutch packs or bands for third gear
- Blocked transmission fluid passages or faulty valve body
- Faulty transmission speed sensors (input or output)
- Internal mechanical transmission failure
What to check before replacing parts
Check the transmission fluid level and condition.
Look for: Low fluid level, burnt smell, or dark color indicating fluid degradation, a leak, or burnt clutches.
Scan for other related DTCs, such as speed sensor or solenoid codes.
Look for: Additional codes that pinpoint an electrical or sensor failure rather than an internal mechanical issue.
Perform a road test while monitoring transmission data on a scan tool.
Look for: Input and output shaft speed sensor readings that do not match the commanded 3rd gear ratio when the PCM commands the shift.
Test the shift solenoids using a bidirectional scan tool or a multimeter.
Look for: Solenoids that fail to click when commanded or show out-of-spec electrical resistance values.
Drop and inspect the transmission oil pan for debris.
Look for: Excessive metal shavings or clutch material in the pan, which indicates internal mechanical failure requiring a rebuild or replacement.
This page explains the generic P0733 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.