P0733: Gear 4 Incorrect Ratio
21 vehicles · 11 makes · $25-$12,000 repair
Most Reported On
P0733 is an OBD-II diagnostic trouble code meaning “Gear 4 Incorrect Ratio.” This code indicates the transmission control module found that the actual gear ratio in 4th gear is outside the acceptable range for that gear. It is detected by comparing transmission input speed against output speed while 4th gear is engaged. A mismatch typically signals the transmission is slipping in 4th gear or that a control/hydraulic fault is preventing proper engagement. This code is most commonly reported on 2011-2026 BMW X3, 2013-2022 BMW X1, and 1996-2002 Mercedes-Benz C-Class, plus 18 other vehicles, with repair costs ranging from $25 to $12,000.
Common Causes
Typical Repair Cost
Based on 25 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0733, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (21)
Transfer Case Actuator Motor Failure
Transfer Case Actuator Motor Failure
Aisin 8-Speed Transmission Jerking
DCT Dual-Clutch Transmission Shudder & Clutch Wear - F82/F83 M4
Transfer Case Failure - xDrive Models E84/F48 X1
xDrive Transfer Case Stress & Fluid Degradation - F98 X4 M / F98 X4 M
xDrive Transfer Case Stress & Fluid Degradation - F97 X3 M / F98 X4 M
Transfer Case Actuator Motor Failure (xDrive AWD System)
xDrive Transfer Case Actuator Motor Failure - E70/F85/F95 X5 M
Transfer Case Actuator Motor Failure (All xDrive Models)
DCT Dual-Clutch Transmission Wear & Judder - F10 M5
SMG Hydraulic Pump and Clutch Actuator Failure
SMG III Hydraulic Pump Failure - E60 M5
5R55W/5R55S Transmission Servo Bore Wear Causing Flare, Slip, and Delayed Reverse
10R80 10-speed transmission harsh/erratic shifting and torque-converter shudder
Automatic transmission overdrive failure (A4LD / 4R55E)
FAQ
What does P0733 mean?
P0733 stands for "Gear 4 Incorrect Ratio." This code indicates the transmission control module found that the actual gear ratio in 4th gear is outside the acceptable range for that gear. It is detected by comparing transmission input speed against output speed while 4th gear is engaged. A mismatch typically signals the transmission is slipping in 4th gear or that a control/hydraulic fault is preventing proper engagement.
What are the most common causes of P0733?
The most common causes of P0733 are: Low or contaminated transmission fluid, Worn 4th-gear clutch packs or bands, Failing shift solenoid for 4th gear, Valve body or line pressure issues, Internal transmission mechanical wear, Restricted transmission filter, Faulty input or output speed sensor. The specific cause varies by vehicle.
How much does it cost to fix P0733?
Repair costs for P0733 range from $25 to $12,000, depending on the vehicle and root cause.
Which vehicles are affected by P0733?
Au7o has documented P0733 across 21 vehicle models from 11 manufacturers: Acura, BMW, Chevrolet, Chrysler, Ford, Jeep, Kia, Lincoln, Mazda, Mercedes-Benz, Nissan.
Sources (12)
- articleMercedes 722.6 5G Transmission Valve Body Conductor Plate Replacement - YouCanic
- articleHere's What A 'Conductor Plate' Is And Why It Kills So Many Mercedes Vehicles - The Autopian
- Forum722.6 Conductor Plate Failure - PeachParts Mercedes-Benz Forum
- ForumSOLVED! - Sudden loss of 3rd/4th gear (4L60E) - GMTNation
- ForumTransmission slipping in 3rd gear - SilveradoSierra.com
- articleMost Common 4L60E Transmission Problems & How to Fix Them - Motorverso
- TSBFord TSB 07-14-6: 5R55S/5R55W flare/bind/delayed engagement concerns
- ForumFord F-150 10-Speed Transmission Lawsuit Over Harsh Shifting - CarComplaints.com
- TSBTECHNICAL SERVICE BULLETIN - 10R80 Harsh/Delayed Shifts (NHTSA TSB PDF)
- articleClass Action Filed Over Ford 10R80 Automatic Transmission Problems - ClassAction.org
- NHTSANHTSA Vehicle Page for 2018 BMW X2 - Complaints and Investigations
- TSBBMW Technical Service Bulletin GBSEL-SELP24 - Transmission Jerking and Delayed Reverse Engagement
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.