P0733 — Gear 3 Incorrect Ratio #

Note: The wording of this trouble code may differ depending on the vehicle manufacturer (OEM). Below are some known variations:

• 3rd Gear Incorrect Ratio (Chrysler, Dodge, Jeep)
• Transmission Gear 3 Ratio Error (Ford, Lincoln, Mercury)
• Gear 3 Ratio Fault (BMW, MINI)
• Incorrect Gear 3 Ratio Detected (GM, Chevrolet, GMC, Cadillac)

Summary of code P0733 #

P0733 is a generic OBD-II (On-Board Diagnostics II) trouble code indicating that the powertrain control module (PCM)—the computer managing your vehicle’s engine and transmission—has detected an abnormal ratio between input and output speeds in third gear of the automatic transmission. These ratios are calculated by comparing data from sensors monitoring the transmission’s input and output shafts. When the PCM finds that the actual gear ratio in third gear does not match the expected ratio set by the OEM, it triggers P0733. This code can point to a wide variety of issues, from mechanical wear to electronic faults, and should not be ignored. Catching it early can prevent more severe transmission damage and costly repairs down the road.

Frequent symptoms for code P0733 #

A vehicle with a P0733 code often shows clear warning signs, especially related to the way it shifts or drives. Sometimes, you may notice subtle changes that are easy to dismiss at first, but can escalate quickly if left unchecked. Typical symptoms include:

• Harsh or delayed shifting into or out of third gear
• Slipping transmission when accelerating in third gear
• Check Engine Light (CEL) illuminated on the dashboard
• Reduced power or limp mode activation (vehicle may limit speed or gear selection)
• Unusual noises such as whining, grinding, or clunking during gear changes
• Poor fuel economy due to improper gear engagement

Likely causes for code P0733 #

A range of issues can trigger the P0733 code, but some causes are more common than others. Pinpointing the root cause requires a systematic approach, as the problem can lie in either the mechanical or electronic components of the transmission system. Here are the most frequent culprits, listed from most to least likely:

1. Faulty shift solenoid (especially the solenoid controlling third gear engagement)
2. Low, dirty, or contaminated transmission fluid
3. Worn or damaged clutch packs (clutches responsible for third gear operation)
4. Malfunctioning transmission control module (TCM) or powertrain control module (PCM)
5. Internal transmission mechanical failure (gears, bands, or bearings)
6. Problems with input or output speed sensors (giving inaccurate readings)
7. Electrical wiring issues (damaged connectors, shorts, or corroded pins)

Step-by-step diagnostic process for P0733 #

Diagnosing P0733 effectively means combining hands-on checks with advanced scan tool readings. Approach the process methodically—like a detective piecing together clues—to avoid misdiagnosis and unnecessary repairs. Here’s how a skilled technician would tackle the code:

• 1. Verify the code using an OBD-II scanner and check for related transmission codes (e.g., P0730, P0731, P0732).
• 2. Inspect transmission fluid level and condition; look for signs of contamination or burnt odor.
• 3. Examine electrical connections at the transmission and related sensors for corrosion, loose pins, or damage.
• 4. Use live data from the scanner to monitor input and output shaft speeds during a test drive, focusing on third gear transitions.
• 5. Test shift solenoids for proper operation using a meter or bi-directional scan tool.
• 6. Perform hydraulic and mechanical checks if fluid and electrical components are in good shape; inspect clutch packs and internal hardware if necessary.
• 7. Consult OEM service bulletins (TSBs) for known issues with your specific vehicle model.

Possible repairs for P0733 #

The solution to a P0733 code depends directly on the diagnosed cause. Addressing the issue promptly may save the transmission from more expensive internal damage. Here are common repairs associated with this code:

• Replace or clean the shift solenoid responsible for third gear
• Flush and replace transmission fluid and filter if contamination or low fluid is found
• Repair or replace damaged wiring or connectors at the transmission or sensors
• Replace faulty speed sensors
• Update or reprogram the TCM/PCM software, if recommended by the OEM
• Rebuild or replace the transmission if internal mechanical failure is confirmed

Is it safe to drive with code P0733? #

Driving with P0733 is not recommended for extended periods. While some vehicles may still operate—sometimes in limp mode (limited performance)—continuing to drive with an unresolved gear ratio error can cause additional transmission damage and leave you stranded. If your vehicle exhibits harsh shifting, slips, or fails to engage third gear, it’s best to limit driving to essential trips only and seek professional repair as soon as possible. In some cases, the vehicle may not shift out of lower gears or may enter limp mode, further restricting safe operation.

Vehicles most commonly affected by P0733 #

While P0733 is a generic code and can occur in any vehicle with an automatic transmission, certain makes and models show a higher incidence due to design or known transmission issues. Vehicles frequently reported with this code include:

• Chrysler, Dodge, Jeep (with 41TE, 42RLE, and 545RFE automatic transmissions)
• Ford, Lincoln, Mercury (with 5R55, 6R60, and 6F35 transmissions)
• GM (Chevrolet, GMC, Cadillac) (with 4L60E, 4L80E, and 6L80 transmissions)
• Honda, Acura (with certain 5-speed and 6-speed automatics)
• BMW, MINI (with ZF or GM automatic transmissions)
• Toyota, Lexus (with Aisin automatic transmissions)

Common mistakes & best practices for P0733 #

Accurate diagnosis and repair of P0733 demand both technical know-how and a logical approach. Avoiding these frequent pitfalls can save time and money:

• Changing the transmission fluid without diagnosing the true cause—fluid issues account for many cases, but not all.
• Replacing the transmission outright before verifying solenoids, sensors, and wiring.
• Ignoring related codes that may help identify a broader transmission fault.
• Skipping OEM technical service bulletins—these often point to common fixes for specific vehicles.
• Failing to clear the code and retest after repairs, which may leave the problem unresolved.

Express FAQ for code P0733 #

Q: Can a simple transmission fluid change fix P0733?
A: Sometimes, yes—especially if the fluid is low, dirty, or burnt. However, if the internal components or solenoids are damaged, a fluid service alone won’t resolve the code.

Q: Does P0733 mean my transmission is failing?
A: Not always. While internal damage is one cause, electrical issues, sensor faults, or even software glitches can also trigger P0733. A thorough step-by-step diagnosis is essential before assuming the worst.