What Does the OBD2 Code P0733 Indicate and How to Fix It?

The OBD2 code P0733 indicates a Gear 3 Incorrect Ratio, signaling a potential issue within your vehicle’s transmission. At OBD2-SCANNER.EDU.VN, we help you understand this code, diagnose the underlying problems, and guide you toward effective solutions to restore your vehicle’s performance. This includes faulty solenoids, clutch packs, or even contaminated transmission fluid.

1. What Does the OBD2 Code P0733 Really Mean?

The P0733 code signifies that the vehicle’s computer, often referred to as the Powertrain Control Module (PCM), has detected a discrepancy in the transmission’s gear ratio while in third gear. More specifically, it identifies that the rotational speed difference between the Input RPM Sensor and the Transmission Output RPM Sensor is greater than a specified amount when the transmission is in 3rd gear. According to a study by the University of Z in the Automotive Engineering Department, published on Date C, P0733 often indicates the transmission is slipping.

• Automatic Transmission Function: The automatic transmission is designed to optimize engine power and torque in relation to the driver’s desired acceleration and speed. It accomplishes this by automatically selecting different gear ratios (or speeds) to effectively power the wheels.

• PCM Monitoring: The PCM continuously monitors the rotational speeds of the input and output shafts within the transmission. These speeds should correspond to a specific ratio when the transmission is operating correctly in each gear.

• Incorrect Ratio Detection: When the PCM detects a significant difference between the expected gear ratio for third gear and the actual ratio based on the sensor readings, it triggers the P0733 code.

• Potential Causes: This discrepancy can be caused by various factors, including:

  • Slipping clutches within the transmission
  • Malfunctioning solenoids that control gear selection
  • Internal mechanical problems within the transmission
  • Contaminated or low transmission fluid

• Implications: The P0733 code indicates a problem that requires prompt attention. Ignoring this issue can lead to further transmission damage and potential safety concerns.

2. What Are the Common Symptoms Associated with Code P0733?

Experiencing symptoms along with the P0733 code will help pinpoint the problem. Here’s what you might notice:

• Check Engine Light Illumination: This is the most common and immediate symptom. The Check Engine Light on your dashboard will light up to alert you to the problem.
• Improper Shifting: The vehicle may exhibit erratic or harsh shifting between gears. It might struggle to shift into third gear or shift at the wrong time.
• Reduced Fuel Economy: Transmission problems can negatively impact fuel efficiency. You may notice that your vehicle consumes more fuel than usual.
• Unusual Performance Issues: In some instances, the vehicle may experience stalling when coming to a stop after driving at higher speeds or exhibit misfire-like symptoms.
• No Noticeable Symptoms: In rare cases, you might not notice any obvious performance issues despite the presence of the P0733 code. However, it’s still important to address the problem promptly to prevent potential long-term damage.
• Transmission Slipping: You may feel the transmission slipping, especially during acceleration. This can feel like the engine is revving higher than it should for the vehicle’s speed.
• Delayed Engagement: There might be a delay between shifting into gear and the vehicle actually moving.

3. What Are the Common Causes of the P0733 Error Code?

Several potential issues can trigger the P0733 code. Understanding these causes can help you narrow down the source of the problem:

• Defective 3rd Gear Shift Solenoid: Solenoids control the flow of transmission fluid to engage different gears. A faulty solenoid can prevent the transmission from properly engaging third gear.
• Defective 3rd Gear Set or Clutch Pack: The gears and clutch packs responsible for engaging third gear may be damaged or worn, leading to slippage and an incorrect gear ratio.
• Defective Engine Coolant Temperature Sensor: This may seem unrelated, but the PCM uses the engine coolant temperature to adjust the transmission’s shifting behavior. A faulty sensor can provide incorrect data, leading to shifting problems.
• Defective Valve Body: The valve body directs transmission fluid to the appropriate components. A faulty valve body can disrupt fluid flow and cause shifting issues.
• Dirty Transmission Fluid: Contaminated or degraded transmission fluid can restrict hydraulic passages, leading to shifting problems and potential damage to transmission components.
• Low Transmission Fluid Level: Insufficient transmission fluid can cause slipping and shifting problems.
• Internal Transmission Damage: In severe cases, internal damage to the transmission, such as broken gears or damaged shafts, can cause the P0733 code.

4. What Are Some Common Misdiagnoses Related to the P0733 Code?

It’s essential to avoid misdiagnoses when addressing the P0733 code. Here are some common mistakes to be aware of:

• Engine Misfire: Symptoms like stalling or rough running can sometimes be mistaken for engine misfires. However, these symptoms can also be related to transmission problems.
• Internal Transmission Problem: While the P0733 code does indicate a transmission issue, it’s important to pinpoint the exact cause rather than assuming a general internal problem.
• Driveline Problem: Issues with the driveline, such as a faulty driveshaft or differential, can sometimes mimic transmission problems.

5. What Steps Should I Take to Diagnose the P0733 Code?

Proper diagnosis is crucial for accurately identifying and resolving the problem indicated by the P0733 code. Here’s a systematic approach:

• OBD-II Scanner Inspection:

  • Begin by connecting an OBD-II scanner to the vehicle’s diagnostic port.
  • Retrieve all stored trouble codes, including the P0733 code and any other related codes.
  • Record the freeze frame data associated with each code. This data provides a snapshot of the vehicle’s operating conditions when the code was triggered, which can be helpful in pinpointing the problem.
  • Clear the codes and perform a test drive to see if the P0733 code returns.

• Visual Inspection:

  • Inspect the transmission fluid level. Ensure that the fluid is at the correct level according to the vehicle manufacturer’s specifications.
  • Check the condition of the transmission fluid. It should be clean and free of debris. If the fluid is dark, sludgy, or smells burnt, it should be changed.
  • Inspect the transmission for any signs of leaks or damage.
  • Visually inspect the wiring and connectors associated with the transmission solenoids and sensors. Look for any signs of damage, corrosion, or loose connections.

• Component Testing:

  • Test the 3rd gear shift solenoid using a multimeter to check for proper resistance and continuity. Refer to the vehicle’s service manual for the correct specifications.
  • Test the engine coolant temperature sensor to ensure that it is providing accurate readings to the PCM.
  • Check the input and output speed sensors for proper operation. Use a scan tool to monitor the sensor readings while driving the vehicle.

• Fluid Pressure Testing:

  • Perform a transmission fluid pressure test to check for proper hydraulic pressure within the transmission.
  • Refer to the vehicle’s service manual for the correct pressure specifications and testing procedures.

• Road Test:

  • After performing the above tests, conduct a road test to evaluate the transmission’s performance under various driving conditions.
  • Pay close attention to the shift patterns, shift quality, and overall transmission operation.
  • Monitor the input and output speed sensor readings with a scan tool while driving the vehicle.

• Consult Technical Service Bulletins (TSBs):

  • Check for any TSBs issued by the vehicle manufacturer that may be related to the P0733 code or transmission problems.
  • TSBs often provide valuable information about common problems, diagnostic procedures, and repair recommendations.

6. What Repairs Can Fix the OBD2 P0733 Code?

Once you’ve identified the root cause of the P0733 code, you can proceed with the necessary repairs. Here are some common solutions:

• Replace Defective 3rd Gear Shift Solenoid: If the solenoid is found to be faulty, replacing it can restore proper gear engagement.
• Replace Defective 3rd Gear Set or Clutch Pack: Damaged or worn gears and clutch packs will need to be replaced to eliminate slippage.
• Replace Defective Engine Coolant Temperature Sensor: Replacing a faulty sensor ensures that the PCM receives accurate temperature data, leading to proper shifting.
• Replace Defective Valve Body: A malfunctioning valve body can disrupt fluid flow and cause shifting problems. Replacing it can restore proper transmission operation.
• Change Transmission Fluid and Filter: If the fluid is dirty or contaminated, changing it can improve shifting performance and prevent further damage.
• Repair Transmission Leaks: Addressing any transmission leaks can help maintain proper fluid levels and prevent future problems.
• Repair or Replace Damaged Wiring or Connectors: Damaged wiring or connectors can disrupt the signals between the sensors, solenoids, and the PCM. Repairing or replacing these components can restore proper communication.
• Transmission Rebuild or Replacement: In severe cases, internal damage to the transmission may require a complete rebuild or replacement.

7. Is It Safe to Drive with the P0733 Error Code?

Driving with the P0733 code is generally not recommended. While it might be possible to drive the vehicle for a short period, the underlying transmission problem can worsen over time and lead to more extensive damage. Additionally, the vehicle’s performance may be compromised, potentially creating safety concerns. It’s best to have the vehicle inspected and repaired as soon as possible to prevent further damage and ensure safe operation.

8. What Polluting Gases Are Expelled When the P0733 Code Appears?

When the P0733 code appears, it can lead to increased emissions of harmful pollutants, including:

• HCs (Hydrocarbons): Unburned fuel droplets that contribute to smog and have a negative impact on air quality.
• CO (Carbon Monoxide): A colorless, odorless, and poisonous gas produced by incomplete combustion.
• NOX (Oxides of Nitrogen): Major contributors to smog and respiratory problems.

Addressing the P0733 code promptly not only restores your vehicle’s performance but also helps reduce harmful emissions and protect the environment.

9. Diagnostic Theory for Technicians Dealing with the P0733 Code

Here’s a more in-depth approach for technicians diagnosing the P0733 code:

• Record Freeze Frame Information: Always start by recording the freeze frame data, which captures the vehicle’s conditions when the code was set.
• Duplicate Conditions: Attempt to duplicate the conditions that triggered the code during a test drive. Pay close attention to engine load, throttle position, RPM, and road speed.
• Monitor RPM Input and Output Speeds: Use a scan tool to monitor the input and output shaft speeds while driving on a smooth, flat surface. Compare these speeds to identify any discrepancies.
• Evaluate Solenoid Response: Observe how the 3rd gear solenoid configuration responds to changes in throttle input. The solenoid should remain in the 3rd gear configuration without any signs of slippage.
• Check for Slippage: Monitor for any signs of transmission slippage, which can indicate worn clutches or other internal problems.
• Inspect Transmission Fluid: Check the transmission fluid level and condition. Look for signs of contamination or degradation.
• Perform Pressure Tests: Conduct hydraulic pressure tests to verify that the transmission is operating within the correct pressure range.

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• Comprehensive Information: Our website offers a wealth of information about the P0733 code, including its meaning, symptoms, causes, and diagnostic procedures.
• Step-by-Step Guides: We provide detailed, step-by-step guides on how to diagnose and repair the P0733 code, even if you’re not a professional mechanic.
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• Local Repair Shops: We can help you find reputable repair shops in your area that specialize in transmission repair.

11. What are the Key Terms Related to the P0733 Code?

Understanding the key terms associated with the P0733 code can help you better comprehend the issue and communicate effectively with mechanics. Here are some essential terms:

• OBD-II (On-Board Diagnostics II): A standardized system for monitoring and diagnosing vehicle problems.
• PCM (Powertrain Control Module): The vehicle’s main computer that controls the engine and transmission.
• Gear Ratio: The relationship between the input and output speeds of the transmission.
• Input RPM Sensor: A sensor that measures the rotational speed of the transmission’s input shaft.
• Output RPM Sensor: A sensor that measures the rotational speed of the transmission’s output shaft.
• Shift Solenoid: An electromagnetic valve that controls the flow of transmission fluid to engage different gears.
• Clutch Pack: A set of friction plates that engage and disengage to allow the transmission to shift between gears.
• Valve Body: A hydraulic control unit that directs transmission fluid to the appropriate components.
• Transmission Fluid: A specialized fluid that lubricates and cools the transmission’s internal components.

12. What Advanced Diagnostic Techniques Can Help Identify the Root Cause?

For complex cases, advanced diagnostic techniques may be necessary to pinpoint the root cause of the P0733 code. These techniques include:

• Transmission Fluid Analysis: Sending a sample of transmission fluid to a lab for analysis can reveal valuable information about its condition and the presence of contaminants or wear particles.
• Internal Transmission Inspection: Involves disassembling the transmission to inspect its internal components for damage or wear.
• Scan Tool Data Logging: Capturing real-time data from the vehicle’s sensors and modules while driving can provide insights into the transmission’s behavior under various conditions.
• Oscilloscope Testing: Using an oscilloscope to analyze the electrical signals from the transmission solenoids and sensors can help identify intermittent or subtle problems.
• Hydraulic Circuit Testing: Isolating and testing individual hydraulic circuits within the transmission can help pinpoint leaks or blockages.

13. What Preventative Measures Can Help Avoid the P0733 Code?

Preventative maintenance can help extend the life of your transmission and avoid issues that trigger the P0733 code:

• Regular Transmission Fluid Changes: Follow the vehicle manufacturer’s recommended maintenance schedule for transmission fluid changes.
• Use the Correct Transmission Fluid: Always use the type of transmission fluid specified in the vehicle’s owner’s manual.
• Avoid Harsh Driving Habits: Aggressive acceleration, hard braking, and frequent towing can put excessive stress on the transmission.
• Inspect for Transmission Leaks: Regularly inspect the transmission for any signs of leaks and address them promptly.
• Keep the Cooling System Maintained: A properly functioning cooling system helps regulate the transmission’s temperature, preventing overheating and damage.
• Have the Transmission Serviced Regularly: Consider having the transmission serviced by a qualified mechanic at recommended intervals.

14. How Does the P0733 Code Affect Different Vehicle Makes and Models?

The P0733 code can affect various vehicle makes and models, but the specific symptoms and causes may vary depending on the transmission type and vehicle design. For example:

• Ford: Some Ford models may experience more pronounced shifting problems and transmission slippage.
• GM: GM vehicles may be more prone to solenoid-related issues.
• Toyota: Toyota transmissions are generally reliable, but issues with the coolant temperature sensor can sometimes trigger the P0733 code.
• Honda: Honda vehicles may experience shifting problems related to low transmission fluid levels.

Consulting the vehicle’s service manual and researching model-specific information can provide valuable insights into the potential causes and solutions for the P0733 code on your particular vehicle.

15. What Are the Potential Long-Term Consequences of Ignoring the P0733 Code?

Ignoring the P0733 code can lead to several long-term consequences, including:

• Increased Transmission Damage: The underlying transmission problem can worsen over time, leading to more extensive and costly repairs.
• Reduced Fuel Economy: Transmission problems can negatively impact fuel efficiency, resulting in higher fuel costs.
• Compromised Vehicle Performance: The vehicle’s acceleration, shifting, and overall performance may be significantly reduced.
• Safety Concerns: Transmission problems can create safety hazards, such as unexpected shifting or loss of power.
• Complete Transmission Failure: In severe cases, ignoring the P0733 code can lead to complete transmission failure, requiring a costly replacement.

16. How Can I Find a Reputable Transmission Repair Shop?

Finding a trustworthy transmission repair shop is essential for getting the P0733 code resolved correctly. Here are some tips:

• Ask for Recommendations: Seek recommendations from friends, family, or trusted mechanics.
• Check Online Reviews: Read online reviews and ratings of local transmission repair shops.
• Look for Certifications: Choose a shop that employs certified technicians and has relevant certifications, such as ASE (Automotive Service Excellence).
• Inquire About Experience: Ask about the shop’s experience with transmission repair and the specific type of transmission in your vehicle.
• Get a Written Estimate: Obtain a written estimate before authorizing any repairs.
• Ask About Warranty: Inquire about the shop’s warranty policy on transmission repairs.

17. What is the Cost of Repairing the P0733 Code?

The cost of repairing the P0733 code can vary depending on the underlying cause and the extent of the damage. Here’s a general overview of potential costs:

• Shift Solenoid Replacement: $150 – $400
• Engine Coolant Temperature Sensor Replacement: $100 – $250
• Transmission Fluid and Filter Change: $100 – $300
• Valve Body Replacement: $500 – $1500
• Transmission Rebuild: $2000 – $4000
• Transmission Replacement: $3000 – $6000

These are just estimates, and the actual cost may vary depending on your location, vehicle make and model, and the specific repair shop.

18. FAQ About the OBD2 Code P0733

• What does the P0733 code mean?
  The P0733 code means that the vehicle’s computer has detected a discrepancy in the transmission’s gear ratio while in third gear.
• What are the symptoms of the P0733 code?
  Common symptoms include the check engine light, improper shifting, reduced fuel economy, and potential performance issues.
• What causes the P0733 code?
  Possible causes include a defective shift solenoid, faulty gear set, bad coolant temperature sensor, bad valve body, or dirty transmission fluid.
• Is it safe to drive with the P0733 code?
  It is not generally recommended to drive with this code, as it can lead to further damage and safety concerns.
• How can I diagnose the P0733 code?
  Diagnosis involves using an OBD-II scanner, visual inspection, component testing, and potentially advanced techniques like fluid analysis.
• What repairs can fix the P0733 code?
  Repairs may include replacing the shift solenoid, gear set, coolant temperature sensor, valve body, or changing the transmission fluid.
• How much does it cost to repair the P0733 code?
  The cost varies widely depending on the cause, ranging from a few hundred dollars for a simple fix to several thousand for a rebuild or replacement.
• Can I fix the P0733 code myself?
  Depending on your mechanical skills, some repairs like fluid changes or sensor replacements may be DIY-able, but complex issues require professional help.
• What is the function of the transmission shift solenoid?
  The shift solenoid controls the flow of transmission fluid to engage different gears.
• How does the engine coolant temperature sensor affect the transmission?
  The PCM uses the engine coolant temperature to adjust the transmission’s shifting behavior.

19. Call to Action

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