OBD-II Trouble Codes

P0733 Code: Gear 3 Incorrect Ratio

Reading Time: 4 minutes

An OBD-II code is designed to tell you any potential issues your vehicle may have. To resolve this code, you must first know what it means. If you’re having trouble figuring out what a P0733 code means and how to fix it, you’ve come to the right place. Read on to learn more about code P0733, the symptoms you should look out for, and the code’s possible triggers.

What Does the P0733 Code Mean?

Diagnostic trouble code (DTC) P0733 stands for “Gear 3 Incorrect Ratio”. This code refers to a potential issue with the operation of third gear in an automatic transmission.

P0733 shows up in vehicles equipped with an automatic transmission when there is trouble shifting into 3rd gear, or while you’re driving in 3rd gear. To increase vehicle speed while maximizing the power output from the engine, computer-controlled automatic transmissions use multiple gear ratios.

The automatic transmission matches the engine’s power and torque characteristics to your desired acceleration rate and speed by auto-selecting different gear ratios or speeds to power your wheels.

Modern cars might have more than four gear ratios. Based primarily on throttle position vs. vehicle speed, the computer determines when to shift down or up.

From various sensors, the Engine Control Module (ECM), Powertrain Control Module (PCM), or Transmission Control Module (TCM) draws valuable input to verify the correct operation of the transmission and its components. To determine the gear ratio and torque converter slip, the input shaft speed sensor is usually calculated against the transmission output shaft speed sensor.

If you notice the P0733 code set in the PCM, this could mean that the powertrain computer is detecting a significant RPM difference between the rotational speed of the input RPM sensor and the transmission output RPM sensor while your car is in 3rd gear. This may happen during shifting or when driving at steady speeds.

The code usually indicates the transmission is slipping. If the result does not match the supposed value, the Diagnostic Trouble Code is set, and you’ll get an illuminated check engine light. Keep in mind that incorrect ratio codes typically require advanced mechanical ability and diagnostic tools.

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In some cases, there may be performance problems due to the P0733 code, such as dying when coming to a stop after driving on the freeway and/or misfire-like symptoms.

Note: The definition of code P0733 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0733 Code?

Here are some common triggers of the error code P0733:

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When the P0733 code sets, the PCM may send a signal to illuminate the check engine light or the malfunction indicator lamp (MIL).

What are the Common Symptoms of the P0733 Code?

Depending on the severity, other related diagnostic trouble codes may also be stored. The check engine light will also be activated. Generally, you may notice the following symptoms if you drive a vehicle with a P0733 trouble code:

How to Diagnose the P0733 Code

Since P0733 is a generic code, it may appear across several makes and models. It can also be triggered by a number of reasons. However, keep in mind that the diagnostic and repair steps for this code still depend on your vehicle’s make and model.

Watch the video below for a better understanding of how to troubleshoot this error code:

How to Fix the P0733 Code

Like most DTC codes, P0733 shares similar triggers and symptoms with several other engine codes. Although this is a generic trouble code, it can’t be resolved with a generic solution. It’s best to leave this matter to the experts if you aren’t confident in your automotive repair skills.

Code P0733 could be triggered by anything from a dirty transmission fluid to an issue with the PCM or TCM, so you must do your research thoroughly before moving to resolve this code.

All vehicles are different, so you should always consult your repair manual and its factory repair information before DIY-ing any repairs. If you’re set on resolving this code yourself, refer to online auto repair sources for guidance. For instance, an ALLDATA subscription provides detailed factory repair information that you can use to accurately resolve issues in your car.

This should help you resolve this error code and be a reference for other repairs you may need to carry out in the future.

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