P0720 means the transmission control module is not receiving a proper signal from the output speed sensor. This sensor measures how fast the transmission output shaft rotates, which determines vehicle speed and helps the TCM calculate gear ratios and shift points.
What does P0720 mean?
P0720 means the transmission control module is not receiving a proper signal from the output speed sensor. This sensor measures how fast the transmission output shaft rotates, which determines vehicle speed and helps the TCM calculate gear ratios and shift points.
P0720 is a transmission-related diagnostic trouble code classified as high severity. When your vehicle's ECU detects this condition, it stores P0720 and illuminates the check engine light.
What are the symptoms of P0720?
If your vehicle has triggered P0720, you may notice one or more of these symptoms:
Check engine light and transmission warning light on
Speedometer not working or reading incorrectly
Harsh or delayed gear shifts
Transmission stuck in limp mode
ABS or traction control warning lights on
Cruise control disabled
What causes P0720?
Here are the most common causes of P0720, ranked by how likely they are to be the culprit:
highFaulty output speed sensor
mediumDamaged or corroded sensor wiring
mediumContaminated or low transmission fluid
lowDamaged tone ring/reluctor on output shaft
lowTCM fault
Is it safe to drive with P0720?
No - address this immediately. Without a valid output speed signal, the transmission cannot manage shift timing and the speedometer may read incorrectly. This affects ABS and stability control systems as well. Drive only to a garage.
How do you diagnose P0720?
Follow these steps to pinpoint the root cause of P0720:
Check if the speedometer is working. A dead speedometer alongside P0720 strongly points to the output speed sensor, since both the transmission and instrument cluster rely on this signal.
Locate the output speed sensor on the transmission housing (typically near the tail shaft or differential housing). Inspect the connector for corrosion, loose pins, or damage.
Measure sensor resistance with a multimeter and compare to manufacturer specifications (typically 300-1200 ohms). Also check for signal voltage while spinning the sensor manually if accessible.
Use a scanner to monitor live data and compare input speed versus output speed readings. The output speed should correlate with vehicle speed and the current gear ratio.
If the sensor and wiring test normal, inspect the transmission fluid for metal contamination. Debris on the magnetic sensor tip can cause signal distortion.
How much does P0720 cost to fix?
Repair costs for P0720 vary depending on the root cause and your vehicle. Here are typical estimates:
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Output speed sensor replacement
€25–€120
€60–€200
€85–€320
Moderate
Sensor wiring repair
€15–€60
€80–€180
€95–€240
Moderate
Transmission fluid and filter change
€50–€150
€80–€200
€130–€350
Moderate
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0720 on specific vehicles
P0720 behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:
P0720 on Mercedes C-Class
Mercedes-Benz C-Class • 2007-2024
The W204 and W205 C-Class with the 722.9 (7G-Tronic) transmission uses a speed sensor integrated into the conductor plate. P0720 on these models typically means the conductor plate is failing and the entire unit needs replacement. Individual sensor replacement is not possible on the 722.9.
Estimated costs for Mercedes C-Class ownersadjusted higher than average due to Mercedes-Benz-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Output speed sensor replacement
€38–€180
€90–€300
€128–€480
Moderate
Sensor wiring repair
€23–€90
€120–€270
€143–€360
Moderate
Transmission fluid and filter change
€75–€225
€120–€300
€195–€525
Moderate
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0720 on Opel Astra
Opel Astra • 2004-2023
The Astra H and J with the Aisin AF17/AF22 automatic transmission trigger P0720 due to the output speed sensor failing from heat exposure. The sensor is located at the bottom of the transmission and is easy to access. A straightforward and inexpensive repair on these models.
What causes P0720 on a Opel Astra?
Opel AstraAF17/AF22 output speed sensor heat degradation
Opel AstraSensor connector corrosion from road spray
P0720 repair cost for Opel Astra
Estimated costs for Opel Astra ownersadjusted lower than average due to Opel-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Output speed sensor replacement
€20–€96
€48–€160
€68–€256
Moderate
Sensor wiring repair
€12–€48
€64–€144
€76–€192
Moderate
Transmission fluid and filter change
€40–€120
€64–€160
€104–€280
Moderate
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0720 on Skoda Octavia
Skoda Octavia • 2004-2024
Octavia models with the DQ200 and DQ250 DSG transmissions share the same output speed sensor design as the VW Golf. On DSG models, the sensor is part of the mechatronic unit, making individual replacement more complex. The conventional 6-speed Aisin automatic used in some Octavias has an externally mounted sensor that is simpler to replace.
Estimated costs for Skoda Octavia ownersadjusted higher than average due to Skoda-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Output speed sensor replacement
€28–€132
€66–€220
€94–€352
Moderate
Sensor wiring repair
€17–€66
€88–€198
€105–€264
Moderate
Transmission fluid and filter change
€55–€165
€88–€220
€143–€385
Moderate
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0720 on Ford Focus
Ford Focus • 2005-2022
Focus Mk2 models with the 4F27E automatic and Mk3 models with the Powershift DCT can both trigger P0720. On the 4F27E, the output shaft sensor is externally mounted and cheap to replace. On the Powershift, the sensor is internal to the TCM housing and failure often requires TCM replacement.
What causes P0720 on a Ford Focus?
Ford Focus4F27E output shaft sensor wear
Ford FocusPowershift DCT internal TCM speed sensor failure
Related diagnostic codes
These codes are often seen alongside P0720 or indicate related issues:
P0720 means the output speed sensor on your transmission is not sending a valid signal. This sensor measures how fast the output shaft spins, which tells the car its road speed and helps the transmission decide when to shift.
Can P0720 cause my speedometer to stop working?
Yes. Many vehicles use the output speed sensor signal for the speedometer. If the sensor fails, your speedometer may read zero or fluctuate wildly, and cruise control will stop working.
Is the output speed sensor easy to replace?
On most vehicles, yes. The sensor is externally mounted on the transmission case and can be replaced with basic tools. The part costs 25-120 EUR and replacement takes 30-60 minutes for a competent DIYer.
Can P0720 affect ABS and traction control?
Yes. The ABS and stability control systems use vehicle speed data. A faulty output speed sensor can trigger ABS and ESP warning lights because the system detects conflicting speed signals.
What is the difference between P0715 and P0720?
P0715 relates to the input (turbine) speed sensor at the front of the transmission, while P0720 relates to the output speed sensor at the rear. The input sensor measures engine-side speed, the output sensor measures wheel-side speed.
Scan your car with Skanyx to diagnose P0720
Connect any Bluetooth OBD2 adapter, scan for codes, and get AI-powered diagnostics with severity ratings and repair cost estimates.
