P0733
Gear 3 Incorrect Ratio
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P0733 means the Powertrain Control Module has detected that the gear ratio in third gear does not match the expected value. The PCM continuously monitors the relationship between the transmission input shaft speed and the output shaft speed. When the vehicle is in third gear and these speeds don't produce the correct ratio, this diagnostic trouble code is set.
Third gear issues tend to be most noticeable during moderate-speed city driving and when transitioning to highway speeds. You might feel the transmission slip, surge, or hesitate during the 2-3 upshift. In some cases, the transmission may skip third gear entirely and jump from second to fourth, or the vehicle may go into a "limp mode" that locks it into a single gear.
As with other gear ratio codes, start by checking the transmission fluid. Low fluid or burnt, dark fluid is a common and relatively inexpensive fix. If the fluid is in good condition, the problem likely requires professional diagnosis. A transmission specialist can perform pressure tests and solenoid function tests to pinpoint whether the issue is electrical (solenoid, wiring, sensor) or mechanical (clutch packs, bands, valve body). Addressing this code promptly helps prevent cascading damage to the transmission.
Severity
Symptoms
- •Slipping or flaring during the 2-3 shift
- •Engine RPMs spike without a corresponding increase in speed
- •Check Engine light illuminated
- •Reduced fuel economy during highway driving
- •Transmission may skip third gear entirely
Likely Causes
Insufficient or contaminated fluid reduces hydraulic pressure needed to fully engage third gear components, leading to slippage and a ratio mismatch.
The clutch pack or band responsible for holding third gear may be worn, allowing slippage that the PCM detects as an incorrect ratio.
The shift solenoid controlling the 2-3 shift may be stuck or malfunctioning, preventing proper hydraulic engagement of third gear.
Worn or sticking valves in the valve body can prevent proper hydraulic routing to the third gear circuit.
A faulty input or output speed sensor can cause incorrect ratio calculations by the PCM.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Service the transmission fluid and filter
- Replace the shift solenoid pack
- Replace faulty speed sensor(s)
- Repair or replace the valve body
- Rebuild or replace the transmission
Shop Parts
Videos
Causes and Fixes P0733 Code: Gear 3 Incorrect Ratio
HVAC Mechanic
What is P0733 : Engine Error Code Causes Explained
Auto User Guide
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