P0720 on a 2017 Ford Mustang
Transmission Output Speed Sensor Malfunction
P0720 on a 2017 Ford Mustang indicates transmission output speed sensor malfunction. It usually stays drivable short-term but should be diagnosed promptly. The most common cause is failed output shaft speed sensor element (typically $150–$500). Confirm the root cause before replacing parts.
What does P0720 mean on a 2017 Ford Mustang?
P0720 is set when the transmission control module does not receive a valid signal from the output shaft speed sensor. The TCM uses this signal to compare actual transmission output to expected output for the selected gear and engine RPM — if the signal is missing or implausible, gear ratio calculations fail and the TCM cannot shift correctly. The vehicle typically drops into limp mode (stuck in a default gear, often 3rd or 4th) until the signal is restored.
This guide covers P0720 across the 2015-2019 Ford Mustang generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2015 through 2019.
Is it safe to drive a 2017 Ford Mustang with P0720?
In most cases a 2017 Ford Mustang stays drivable for short trips with P0720 active, but diagnose and repair it promptly. This is a high-severity code — ignoring it can lead to further damage or a failed emissions test.
What are the symptoms of P0720 on a 2017 Ford Mustang?
- Check Engine Light is illuminated
- Speedometer reads zero or fluctuates erratically
- Transmission locked into a single gear (limp mode)
- Hard, harsh, or no shifts
- Cruise control inoperative
- Vehicle may shudder or hesitate at the moment of shift
- Often paired with P0700 (transmission control malfunction)
What causes P0720 on a 2017 Ford Mustang?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Failed output shaft speed sensor element | Most common | $150–$500 |
| Damaged sensor connector or harness | Common | $80–$350 |
| Metal debris on the sensor tip (from internal transmission wear) Cleaning the sensor face is a free first attempt. | Common | $100–$400 |
| Damaged tone ring or reluctor wheel inside the transmission | Occasional | $1,500–$4,500 |
| Transmission fluid contamination preventing the sensor from reading | Occasional | $200–$700 |
| Wiring fault between the sensor and the TCM | Occasional | $100–$500 |
| Failed TCM signal input (rare) | Rare | $500–$1,500 |
How to diagnose this on a 2017 Ford Mustang
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Locate the output speed sensor on this transmission
The output shaft speed sensor is typically a two-wire sensor threaded into the rear of the transmission case (RWD vehicles) or the side of the transaxle (FWD vehicles). Some vehicles have it on the transfer case for 4WD. Confirm location in the service manual.
Tools: Vehicle-specific service information
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Check connector and visible wiring
Sensor connectors near the transmission case are exposed to heat, road debris, and sometimes fluid leaks. Unplug and inspect for corrosion, transmission fluid migration up the harness, or visible damage. Clean and re-seat.
Tools: Connector unlock tool, Electrical contact cleaner
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Measure sensor resistance
Most output speed sensors are magnetic or Hall-effect with a typical resistance of 200–1500 Ω. Compare to the service manual. Infinite resistance means an open sensor; near zero means shorted. Either way, replace.
Tools: Multimeter, Service spec sheet
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Verify signal output during rotation
On a lift with the rear wheels free to rotate, spin a rear wheel slowly by hand while watching the output speed PID. The reading should change in proportion to wheel rotation. No response confirms a dead sensor or damaged tone ring.
Tools: Vehicle lift, Scan tool with output speed PID
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Inspect sensor tip for debris
Remove the sensor and look at the magnetic tip. Steel slivers stuck to the magnet are normal — large chunks or clutch material is a warning sign that the transmission is shedding material. Clean the tip and reinstall as a first attempt; consider transmission fluid analysis if heavy debris was present.
Tools: Socket, Magnet pick or wire brush
Known Technical Service Bulletins for the 2015-2019 Ford Mustang
Manufacturers publish Technical Service Bulletins (TSBs) when a known issue affects a specific vehicle. These bulletins come from the NHTSA database for your Ford Mustang.
- UNKNOWN OR OTHER Feb 23, 2026
Ford and Lincoln vehicles equipped with wired keyless entry keypad systems and accessory wireless keyless entry keypad systems may or may not come with a wallet card containing the master code. Unlike the integrated wired keypad, the accessory wireless keypad master code cannot be retrieved from the vehicle using a diagnostic scan tool or from the label printed on the body control module (BCM). The Factory Keyless Entry Code application within the diagnostic scan tool will not provide an applicable master code for the accessory wireless keypad. If the wallet card for an accessory keypad is not available, the "Wireless RF Keypad Diagnosis Guide" can be referenced and provides direction on how to retrieve the master code. This guide is located under the Workshop Manual tab > Accessories > Installation > Wireless RF Keypad Diagnosis Guide > PPT C > Step C2.<br /><br /> Note: The only available keypad for some vehicles from the assembly plant is the accessory wireless keyless entry keypad. The integrated wired keypad cannot be installed on vehicles not equipped from the factory with a wired keyless entry k
NHTSA #11029052 - ELECTRICAL SYSTEM Feb 23, 2026
Ford and Lincoln vehicles equipped with wired keyless entry keypad systems and accessory wireless keyless entry keypad systems may or may not come with a wallet card containing the master code. Unlike the integrated wired keypad, the accessory wireless keypad master code cannot be retrieved from the vehicle using a diagnostic scan tool or from the label printed on the body control module (BCM). The Factory Keyless Entry Code application within the diagnostic scan tool will not provide an applicable master code for the accessory wireless keypad. If the wallet card for an accessory keypad is not available, the "Wireless RF Keypad Diagnosis Guide" can be referenced and provides direction on how to retrieve the master code. This guide is located under the Workshop Manual tab > Accessories > Installation > Wireless RF Keypad Diagnosis Guide > PPT C > Step C2.<br /><br /> Note: The only available keypad for some vehicles from the assembly plant is the accessory wireless keyless entry keypad. The integrated wired keypad cannot be installed on vehicles not equipped from the factory with a wired keyless entry k
NHTSA #11029052 - STRUCTURE Feb 23, 2026
Ford and Lincoln vehicles equipped with wired keyless entry keypad systems and accessory wireless keyless entry keypad systems may or may not come with a wallet card containing the master code. Unlike the integrated wired keypad, the accessory wireless keypad master code cannot be retrieved from the vehicle using a diagnostic scan tool or from the label printed on the body control module (BCM). The Factory Keyless Entry Code application within the diagnostic scan tool will not provide an applicable master code for the accessory wireless keypad. If the wallet card for an accessory keypad is not available, the "Wireless RF Keypad Diagnosis Guide" can be referenced and provides direction on how to retrieve the master code. This guide is located under the Workshop Manual tab > Accessories > Installation > Wireless RF Keypad Diagnosis Guide > PPT C > Step C2.<br /><br /> Note: The only available keypad for some vehicles from the assembly plant is the accessory wireless keyless entry keypad. The integrated wired keypad cannot be installed on vehicles not equipped from the factory with a wired keyless entry k
NHTSA #11029052 - VISIBILITY/WIPER Jan 5, 2026
Certain 2015-2019 Model Year Multiple Vehicle Lines Rear View Camera Inspection For One-Time Replacemen
NHTSA #11027801 - VISIBILITY/WIPER Dec 22, 2025
Certain 2015-2019 Model Year Multiple Vehicle Lines Rear View Camera Inspection For One-Time Replacement
NHTSA #11026915 - UNKNOWN OR OTHER Dec 22, 2025
Certain 2015-2019 Model Year Multiple Vehicle Lines Rear View Camera Inspection For One-Time Replacement
NHTSA #11026915
+14 more TSBs available in MECH AI's TSB explorer for this vehicle.
NHTSA complaints & recalls for the 2017 Ford Mustang
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2017 Ford Mustang. Use these to gauge how common a problem is on your specific vehicle before you start chasing Ford Mustang diagnostics.
- ENGINE 26
- BACK OVER PREVENTION 62
- UNKNOWN OR OTHER 36
- STRUCTURE 36
- ELECTRICAL SYSTEM 31
6 active recalls
- ENGINE AND ENGINE COOLING:COOLING SYSTEM:HOSES/LINES/PIPING/FITTINGS Oct 2016
Ford Motor Company (Ford) is recalling certain model year 2015-2017 Mustang vehicles manufactured February 24, 2015, to August 30, 2016. A hose may separate from the engine oil cooler tube assembly causing an oil leak.…
NHTSA campaign 16V779000 - AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE Aug 2017
Ford Motor Company (Ford) is recalling certain 2017 F-150 and Mustang vehicles. The air bag inflator within the passenger frontal air bag module may rupture in the event of a crash.…
NHTSA campaign 17V529000 - LATCHES/LOCKS/LINKAGES:DOORS:LATCH Mar 2017
Ford Motor Company (Ford) is recalling certain 2017 Ford Mustang vehicles. The return spring for the driver side interior door handle may come loose, allowing the driver's door to unlatch in a side impact crash. As such, these vehicles fail to comply with the requirements of Fe…
NHTSA campaign 17V168000 - BACK OVER PREVENTION: SENSING SYSTEM: CAMERA Feb 2022
Ford Motor Company (Ford) is recalling certain 2015-2017 Mustang vehicles. The rearview camera wiring may be loose or damaged, which can result in a blank or distorted image.…
NHTSA campaign 22V082000
How do I fix P0720 on a 2017 Ford Mustang?
- Clean debris off the output speed sensor tip
- Replace the output shaft speed sensor with an OEM part
- Repair sensor connector or harness damage
- Service transmission fluid (drop pan, replace filter and gasket)
- Internal transmission repair if tone ring or shaft damage is confirmed
About the 2015-2019 Ford Mustang
The 2015-2019 Ford Mustang was commonly sold with the following powertrains: 2.3L EcoBoost I4, 5.0L V8, 5.2L V8. Common trims include EcoBoost, GT, Mach 1, Shelby GT500, Dark Horse.
Why P0720 puts the transmission into limp mode
The TCM continuously compares output shaft speed to engine RPM and selected gear to verify it is actually getting the gear ratio it commanded. Without a valid output speed signal:
- Ratio verification fails (sets P0731-P0734 in some cases)
- Shift point timing breaks (cannot tell vehicle speed for upshifts)
- Torque converter lockup logic fails (depends on accurate speed)
Limp mode is a protection — the TCM picks a safe default gear and holds it until the signal returns. Drive a short distance to a shop; do not attempt long trips in limp mode.
P0720 with metal on the sensor tip
A small amount of metallic dust on the magnetic sensor tip is normal — it’s the natural wear of bearings and gears over the life of the transmission. Large flakes or clutch material is not normal and indicates internal damage that will eventually cause shifting problems beyond the sensor. If you find heavy debris, do a fluid service and inspect the pan magnet too — together they tell the story of what’s happening inside.
P0720 vs P0500 (Vehicle Speed Sensor)
These can look similar but come from different sources:
- P0500 — vehicle speed signal missing (often the ABS wheel speed sensor on modern vehicles)
- P0720 — transmission output shaft speed signal missing specifically from the transmission’s own sensor
On vehicles where the TCM derives “vehicle speed” from the output shaft sensor, both codes can set together from a single sensor failure.