P0733: Gear 4 Incorrect Ratio
23 vehicles · 7 makes · $100-$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 2007-2026 BMW X5, 2011-2026 BMW X3, and 2016-2021 BMW M2, plus 20 other vehicles, with repair costs ranging from $100 to $12,000.
Common Causes
Typical Repair Cost
Based on 27 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
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Vehicles Affected (23)
Transfer Case Actuator Motor Failure
Transfer Case Actuator Motor Failure
DCT (M-DCT) Mechatronics Unit Failure
Transfer Case Actuator Motor Failure
SMG Hydraulic Pump and Clutch Actuator Failure
Transfer Case Failure - xDrive Models E84/F48 X1
Aisin 8-Speed Transmission Jerking
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)
SMG III Hydraulic Pump Failure (M6 and SMG-Equipped 645Ci/650i)
DCT Dual-Clutch Transmission Shudder & Clutch Wear - F82/F83 M4
xDrive Transfer Case Actuator Motor Failure - E70/F85/F95 X5 M
ZF 8HP Transmission Mechatronic Issues (All 8 Series & M8)
Transfer Case Actuator Motor Failure (All xDrive Models)
ZF 6HP Transmission Mechatronic Sleeve & Valve Body Failure
Automatic Transmission No-Reverse / Failsafe Due to ZF 5HP19 Drum and Valve Body Wear
DCT Dual-Clutch Transmission Wear & Judder - F10 M5
DCT Dual-Clutch Transmission Shudder & Clutch Wear - F87 M2/M2C
SMG III Hydraulic Pump Failure - E60 M5
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 $100 to $12,000, depending on the vehicle and root cause.
Which vehicles are affected by P0733?
Au7o has documented P0733 across 23 vehicle models from 7 manufacturers: Acura, BMW, Chrysler, Ford, Lincoln, Mercedes-Benz, Nissan.
Sources (12)
- NHTSANHTSA Vehicle Page for 2007 BMW M6 - includes complaints and investigations related to SMG transmission issues
- videoYouTube Repair Video by 'BMW Repair Guide': Replacing SMG Hydraulic Pump on BMW M6 E63
- ForumBimmerpost X1 Forum - Transfer case actuator gear / xDrive malfunction discussion
- NHTSANHTSA Vehicle Page for 2018 BMW X2 - Complaints and Investigations
- TSBBMW Technical Service Bulletin GBSEL-SELP24 - Transmission Jerking and Delayed Reverse Engagement
- ForumReddit r/BMW Discussion: 2018 BMW X2 Transmission Jerking Problem
- ForumBimmerpost X3M/X4M Forum - Transfer case fluid service interval discussion for F97/F98
- TSBTSB 23-2250 - 10R60/10R80/10R80 MHT Harsh/Delayed Engagement And/Or Shift (NHTSA)
- TSB10R60/10R80/10R80 MHT Automatic Transmission - 2021-2023 Ford & Lincoln (Ford OEMDTC)
- articleClass Action Filed Over Ford 10R80 Harsh Shifting
- articleMercedes 722.6 5G Transmission Valve Body Conductor Plate Replacement - YouCanic
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.