P0720: Output Speed Sensor Circuit Malfunction
7 vehicles · 5 makes · $150-$6,500 repair
Most Reported On
P0720 is an OBD-II diagnostic trouble code meaning “Output Speed Sensor Circuit Malfunction.” P0720 indicates a malfunction in the transmission output speed sensor circuit. The output speed sensor measures how fast the transmission's output shaft is turning, which the computer uses to calculate vehicle speed, control shift timing, and manage torque converter lockup. When the signal is missing or implausible, the transmission may shift harshly, get stuck in one gear (limp mode), or the speedometer may read incorrectly. The fault is usually in the sensor, its wiring, or the connector, though internal transmission issues can also be responsible. This code is most commonly reported on 2003-2012 Mercedes-Benz E-Class (E320, E350, E500, E550), 2005-2013 Mercedes-Benz C-Class (C230, C280, C300, C350), and 1990-1995 Chrysler LeBaron, plus 4 other vehicles, with repair costs ranging from $150 to $6,500.
Common Causes
Typical Repair Cost
Based on 8 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0720, 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 (7)
7G-Tronic Conductor Plate Failure
7G-Tronic Valve Body Failure
722.6 5G-Tronic conductor plate failure (limp mode, stuck in 2nd gear)
7G-Tronic Conductor Plate / Speed Sensor Failure
FAQ
What does P0720 mean?
P0720 stands for "Output Speed Sensor Circuit Malfunction." P0720 indicates a malfunction in the transmission output speed sensor circuit. The output speed sensor measures how fast the transmission's output shaft is turning, which the computer uses to calculate vehicle speed, control shift timing, and manage torque converter lockup. When the signal is missing or implausible, the transmission may shift harshly, get stuck in one gear (limp mode), or the speedometer may read incorrectly. The fault is usually in the sensor, its wiring, or the connector, though internal transmission issues can also be responsible.
What are the most common causes of P0720?
The most common causes of P0720 are: Failed output (vehicle) speed sensor, Damaged wiring, connector, or corrosion in the sensor circuit, Metal debris on the sensor tip or damaged reluctor ring, Open or short in the signal circuit, Low or contaminated transmission fluid affecting components, Poor ground or reference voltage to the sensor, Faulty transmission control module (TCM/PCM). The specific cause varies by vehicle.
How much does it cost to fix P0720?
Repair costs for P0720 range from $150 to $6,500, depending on the vehicle and root cause.
Which vehicles are affected by P0720?
Au7o has documented P0720 across 7 vehicle models from 5 manufacturers: Chrysler, Hyundai, Lincoln, Mercedes-Benz, Nissan.
Sources (12)
- manufacturerECU Testing: Mercedes 7G-Tronic TCM conductor plate failure
- mediaMB Medic: 722.9 7G-Tronic Valve Body & Conductor Plate Must Read
- manufacturerUpFix: 722.9 Transmission Conductor Plate Repair Could Save $1000s
- mediaThe Autopian: Heres What A Conductor Plate Is And Why It Kills So Many Mercedes Vehicles
- otherCarComplaints: Mercedes 722.9 7G-Tronic Transmission Problems Cause Lawsuit
- mediaMB Medic: 722.9 7G Tronic Automatic Transmission Problems and Solutions
- mediaTransmission Repair Cost Guide: 722.9 Valve Body Problems & Solutions
- articleMercedes 722.6 5G Transmission Valve Body Conductor Plate Replacement - YouCanic
- Forum722.6 Conductor Plate Failure - PeachParts Mercedes-Benz Forum
- RecallFord Recalls F-150, Bronco, Mustang, Explorer, Lincoln Aviator Over Transmission Issue
- RecallFord 10R80 Automatic Transmission Recalled Over Shifting Issue
- ForumExperiencing Hard Shifting and Bumps in 2020 Lincoln Aviator Reserve - Lincoln Forums
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.