P0733
Gear 3 Incorrect Ratio.
- Generic
- Powertrain
- Generic code
- High severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- 33
- FaultThe specific fault in that area
What it means
P0733 means the transmission control module has detected that the actual ratio in third gear does not match the expected ratio. It calculates the ratio by comparing input shaft speed with output shaft speed, and when the result is outside the allowed tolerance for long enough it sets the code. This usually points to slipping clutches or bands, a hydraulic pressure problem or a faulty speed signal.
Symptoms
- Engine revs flare or rise without matching acceleration when shifting into or holding third gear
- Slipping in third gear, especially under load or going uphill
- Harsh, delayed or slurred shift into or out of third
- Transmission warning light or malfunction indicator lamp on
- Transmission going into limp mode, often stuck in one gear
- Poor fuel economy and sluggish acceleration
Possible causes
- Low, degraded or contaminated transmission fluidlikely
- Worn clutch packs or bands for third gear causing internal sliplikely
- Low line pressure from a worn pump, blocked filter or internal leakspossible
- Faulty shift solenoid or pressure control solenoid, or a sticking valve body valvepossible
- Faulty input or output speed sensor, or damaged wiring or connector giving an incorrect signalpossible
- Torque converter fault, such as clutch slip or internal failure (depends on transmission design)rare
- Outdated transmission control software where the manufacturer has issued a known fix for the modelrare
How to diagnose
- Read all stored codes and freeze frame data, noting road speed, gear, load and fluid temperature when the fault set, and look for other transmission or speed sensor codes
- Check the transmission fluid level, condition and smell using the procedure for the specific model, as some units are sealed and need a specific temperature
- Inspect the wiring and connectors to the speed sensors, solenoids and transmission harness for damage, corrosion, chafing or fluid ingress
- Using live data, compare input and output speed readings and the calculated gear ratio in each gear to find where the slip occurs
- Check the commanded and actual line pressure if the model supports it, and test solenoid operation and resistance against the manufacturer's specification
- Road test under varying loads and note whether the slip is constant, only when hot or only in third
- Check for technical service bulletins and available software updates for the vehicle and transmission
- If the fault persists, inspect the pan for debris or clutch material and assess the valve body and internal components
How to fix
- Correct the fluid level or replace degraded fluid and filter using the specified fluid type
- Replace faulty speed sensors or repair damaged wiring and connectors
- Replace the faulty shift or pressure solenoid, or overhaul or replace the valve body
- Overhaul or replace the transmission, including worn clutches, bands and seals, if internal wear is confirmed
- Replace or repair the torque converter if it is found to be the cause
- Update the transmission control software only if the manufacturer lists it as a fix for this fault on the vehicle
Can I keep driving?
High severity
Limit driving and avoid heavy loads, as continued slipping can quickly overheat and damage the transmission. Get it diagnosed promptly, and stop driving if slipping is severe or the car will not hold a gear.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.