P073F: Unable to Engage Gear 1
3 vehicles · 1 makes · $150-$3,500 repair
Most Reported On
P073F is an OBD-II diagnostic trouble code meaning “Unable to Engage Gear 1.” This powertrain code indicates the transmission was unable to engage 1st gear when commanded by the transmission computer. It belongs to the modern transmission gear-engagement code series. The computer detected that first gear did not engage as requested, which can stem from a hydraulic, electrical, or internal mechanical problem. The result can be poor launch/acceleration or limp mode, so it should be diagnosed promptly to prevent further transmission damage. This code is most commonly reported on 2019-2023 Mercedes-Benz A-Class (A220), 2020-2025 Mercedes-Benz GLB (GLB250), and 2013-2019 Mercedes-Benz B-Class (B250, B250e), with repair costs ranging from $150 to $3,500.
Common Causes
Typical Repair Cost
Based on 3 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
This is a powertrain code, so a basic OBD-II reader can read it. These read P073F.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the 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 tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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Vehicles Affected (3)
FAQ
What does P073F mean?
P073F stands for "Unable to Engage Gear 1." This powertrain code indicates the transmission was unable to engage 1st gear when commanded by the transmission computer. It belongs to the modern transmission gear-engagement code series. The computer detected that first gear did not engage as requested, which can stem from a hydraulic, electrical, or internal mechanical problem. The result can be poor launch/acceleration or limp mode, so it should be diagnosed promptly to prevent further transmission damage.
What are the most common causes of P073F?
The most common causes of P073F are: Faulty shift solenoid, Valve body fault or stuck valve, Low or contaminated transmission fluid, Worn first-gear clutch/internal mechanical fault, Wiring or connector fault in the transmission circuit, Faulty transmission control module. The specific cause varies by vehicle.
How much does it cost to fix P073F?
Repair costs for P073F range from $150 to $3,500, depending on the vehicle and root cause.
Which vehicles are affected by P073F?
Au7o has documented P073F across 3 vehicle models from 1 manufacturers: Mercedes-Benz.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.