P0733 Incorrect 3rd gear ratio
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P0951 – OBD-II Trouble Code Technical Description
Trouble code P0733 indicates that the PCM has detected an incorrect 3rd gear ratio.
What does the fault code mean P0733?
Trouble code P0733 means that the automatic transmission control module (PCM) has detected a problem when shifting into third gear. When the vehicle is equipped with an automatic transmission, the PCM compares the actual gear ratio with the value specified by the manufacturer. If a discrepancy is detected, DTC P0733 is issued. This may indicate problems with the transmission that require diagnosis and repair.
Possible reasons
Possible causes for DTC P0733:
- Low or contaminated transmission fluid: Insufficient or contaminated transmission fluid can cause the transmission to malfunction.
- Defective Speed Sensors: Faulty speed sensors may provide incorrect wheel or transmission shaft speed data, which can cause P0733.
- Shift Valve Problems: Defective or clogged shift valves can cause delays or incorrect shifting.
- Worn or damaged internal transmission components: Worn or damaged clutches, discs, pistons, or other internal transmission components can also cause P0733.
- Electrical Connection Problems: Poor electrical connections, breaks or short circuits in the transmission control system can cause operating errors.
- PCM Software: Incorrect software in the PCM can cause the transmission to operate incorrectly.
What are the symptoms of trouble code P0733?
Symptoms that may occur when you have a P0733 trouble code can vary depending on the specific cause and severity of the problem, some of the possible symptoms are:
- Unusual transmission behavior: This may include jerking, jolting, or unusual noises when shifting gears, especially when shifting into third gear.
- Shift Delay: The vehicle may slow down in its response to shift commands, resulting in delays when changing speed or engine speed.
- Increased fuel consumption: If the transmission does not shift to third gear correctly, it may cause increased fuel consumption due to insufficient transmission efficiency.
- Changes in engine performance: For example, the engine may operate at higher speeds than normal or exhibit other unusual characteristics due to an incorrect gear selection.
- Error indicators on the instrument panel: Warning lights, such as “Check Engine” or transmission indicators, may appear on the instrument panel.
- Emergency mode: In some cases, the PCM may put the transmission into limp mode to protect against further damage. This may result in speed throttling or other functionality limitations.
If you experience any of these symptoms, it is recommended that you contact a qualified mechanic to diagnose and repair the problem.
How to diagnose a fault code P0733?
Diagnosing the problem with trouble code P0733 requires a certain approach and the use of specialized tools. Here is a general plan of action for diagnosis:
- Checking fault codes: First, connect the car scanner to the OBD-II diagnostic connector and read the trouble codes. If you detect a P0733 code, this will be the starting point for further diagnosis.
- Checking the level and condition of the transmission fluid: Check the level and condition of the transmission fluid. Low levels or contamination may be causing the problem. The fluid must be in good condition and at the correct level.
- Checking speed sensors: Check the operation of the speed sensors, which can provide information about the rotation speed of the wheels and the transmission shaft. Defective sensors can cause an erroneous determination of the gear ratio.
- Checking electrical connections and wiring: Check the electrical connections and wiring related to the transmission. Poor contacts or breaks can cause transmission errors.
- Checking the gearshift valves: Test and diagnose the shift valves to ensure they are functioning properly and are not stuck.
- Checking the internal components of the gearbox: If everything else looks normal, you may need to inspect the internal components of the transmission for wear or damage.
- PCM Software Check: If no other causes are found, the PCM software may need to be checked for updates or corruption.
For a complete and accurate diagnosis, it is recommended that you contact a qualified mechanic or auto repair shop equipped with the appropriate tools and experience in dealing with transmission problems.
Diagnostic errors
When diagnosing the P0733 trouble code, various errors can occur that can make it difficult to pinpoint and resolve the problem. Some of the potential errors:
- Insufficient diagnosis: Some mechanics may focus only on the transmission without checking other possible causes such as speed sensors or electrical connections.
- Faulty hardware: Using inappropriate or faulty diagnostic equipment may lead to incorrect conclusions about the condition of the transmission or other vehicle systems.
- Skipping a thorough check: Skipping a thorough check of every aspect of the transmission, including transmission fluid, sensors, valves, internal components, and PCM software, may result in missing factors that could be the source of the problem.
- Incorrect diagnosis of corrective factors: Sometimes mechanics may focus only on the symptoms and not pay attention to factors that may lead to an incorrect determination of the cause, such as faulty PCM software.
- Insufficient knowledge and experience: Insufficient knowledge or experience with transmissions and transmission control systems may lead to incorrect conclusions and repair recommendations.
- Ignoring manufacturer's recommendations: Some mechanics may ignore the vehicle manufacturer's recommendations for diagnosis and repair, which may result in incorrect repairs or replacement of unnecessary components.
To avoid these mistakes, it is important to contact experienced and qualified mechanics who have the necessary knowledge, experience and equipment to properly diagnose and repair your vehicles. You should also rely on the vehicle manufacturer's recommendations when performing diagnostics and repairs.
How serious is the fault code? P0733?
Trouble code P0733 indicates a problem in the automatic transmission, which can be serious for the operation and safety of the vehicle. It is important to understand that this error is associated with improper shifting into third gear, which can lead to a number of problems such as loss of power, increased fuel consumption, damage to internal transmission components, and even potentially dangerous situations on the road.
Depending on the specific cause of the error, the impact may vary. For example, if the cause of the error is low transmission fluid, simply adding fluid may solve the problem. However, if the problem is more serious, such as wear on internal transmission components, then major repairs or component replacement may be required.
Ignoring the P0733 code can lead to deterioration of the transmission and additional damage, which increases the cost of repairs and the risk of an accident. Therefore, it is important to immediately contact a qualified mechanic to diagnose and repair the problem as soon as this error appears.
What repair will help eliminate the code? P0733?
Troubleshooting the P0733 trouble code may involve several possible repair steps, depending on the specific cause of the code. Below are some of them:
- Checking and replacing transmission fluid: If the cause of the error is low or contaminated transmission fluid, the first step may be to check the fluid level and condition. If the fluid is dirty or insufficient, the transmission fluid and filter must be replaced.
- Diagnostics and replacement of speed sensors: If the speed sensors are faulty, they must be diagnosed and replaced. This is important because incorrect data from the sensors can lead to an erroneous determination of the gear ratio.
- Repair or replacement of gear shift valves: Defective or stuck shift valves can cause the transmission to malfunction. Repairing or replacing them may solve the problem.
- Repair or replace internal transmission components: If the error is caused by wear or damage to internal transmission components such as clutches, discs, pistons and other parts, they may need to be repaired or replaced.
- PCM Software Update: Sometimes the problem may be related to the PCM software. In such cases, a software update may help resolve the issue.
- Additional repair measures: Depending on the diagnosis, other repair measures may be necessary, such as replacing or repairing wiring, correcting electrical connections, etc.
It is important to contact a qualified mechanic or auto repair shop to diagnose and repair the problem, as proper repair requires determination of the specific cause of the error and professional skills.
P0733 – Brand-specific information
Trouble code P0733 is also associated with problems in the automatic transmission and refers to an incorrect gear ratio. Here's how it can be deciphered for some well-known car brands:
- Ford: P0733 – Incorrect third gear ratio. This error indicates problems with the third gear shift in the transmission.
- Chevrolet / GMC: P0733 – Incorrect third gear ratio. This error is also associated with problems with the third gear shifting in the gearbox.
- Toyota: P0733 – Incorrect third gear ratio. This error indicates problems with the third gear shift in the transmission.
- Honda: P0733 – Incorrect third gear ratio. This error is also associated with problems with the third gear shifting in the gearbox.
- BMW: P0733 – Incorrect third gear ratio. This error can indicate various problems with the transmission, such as wear on the clutch, speed sensors, or hydraulic system.
For a more accurate interpretation of the P0733 code for a specific vehicle make, it is recommended that you consult official repair manuals or qualified auto repair technicians.
