No recalls found in NHTSA database
Note on data: The provided dataset shows no owner complaints and no official recalls for the 2020–2024 Subaru Outback related to P0720. P0720 is an OBD-II diagnostic trouble code (DTC) that points to an issue with the transmission output speed sensor circuit. Because there are no recalls/TSBs listed in the data you supplied, this guide references general diagnosis knowledge and common Subaru-specific patterns, while clearly stating data limitations.
CODE MEANING AND SEVERITY
- What P0720 means: P0720 = Output Speed Sensor Malfunction. The vehicle’s powertrain control module (PCM) detects an irregular or missing signal from the transmission’s output speed sensor (OSS/VSS) circuit.
- Why it matters on a 2020–2024 Subaru Outback: The OSS/VSS provides the speed signal used by the PCM/TCU for shift logic, speedometer display, and some transmission control functions. A faulty signal can lead to incorrect shifting behavior, dash speedometer inaccuracies, and/or loss of cruise control functionality. In some vehicles, the PCM may enter a failsafe or “limp” mode if the signal is unreliable.
- Severity: Medium to potentially high. The code can cause drivability issues and incorrect shifting, and it may reveal an intermittent wiring fault or sensor failure that could worsen over time if not addressed.
COMMON CAUSES ON SUBARU OUTBACK
- Faulty transmission output speed sensor (OSS) itself.
- Damaged, corroded, or loose wiring or connector to the OSS/VSS (pin corrosion, moisture ingress, bent pins, damaged insulation).
- Faulty or damaged tone wheel/reluctor ring inside the CVT (mechanical issue preventing reliable pulses from the sensor).
- Ground or power supply issues to the OSS sensor (faulty 5V reference, poor ground connection).
- Transmission control module software issues or a need for a software update (less common but possible).
- Water intrusion or aftermarket modifications affecting sensor wiring.
- In some cases, related speed sensor circuits (e.g., vehicle speed sensor, other speed sensors) that share grounds or grounds can contribute to intermittent signals.
SYMPTOMS
- Check engine light (MIL) with code P0720 stored.
- Speedometer may read inaccurately, lag, or stop displaying correct vehicle speed.
- Cruise control may disengage or fail to maintain set speed.
- Shifting irregularities, harsh or delayed shifting, or occasional limp/failsafe mode.
- May notice transmission harshness or unexpected upshifts/shifts.
- In rare cases, no obvious drivability issue aside from the MIL and speedometer symptoms.
DIAGNOSTIC STEPS
Preliminary: Safety first—park safely, use a well-lit workspace, and ensure the vehicle is in Park (Automatic) or Neutral with parking brake engaged when inspecting electrical connections.
A. Read DTCs and data streams
- Use a reliable OBD-II scan tool to confirm P0720 and note any freeze-frame data.
- Check for related codes commonly seen with P0720 (see “Related Codes” section) such as P0721, P0722, P0715, or P0500.
- While monitoring live data, observe the OSS/VSS signal or Vehicle Speed Sensor signal and the PCM’s sensor reference/gnd behavior if your scan tool provides live PID data.
B. Inspect the OSS/VSS wiring and connections
- Locate the transmission output speed sensor (OSS/VSS) on the Outback’s CVT, usually mounted on the transmission bell housing area or near the output shaft.
- Inspect the sensor connector and wiring for:
- Loose or corroded pins
- Damaged insulation, chafed harness, or exposed wires
- Signs of water intrusion or oil/wet contamination
- Secure mounting and proper connector latch engagement
- Clean or reseat the connector; if corrosion is present, clean with electrical contact cleaner and apply dielectric grease if appropriate.
C. Verify sensor power and ground
- With a multimeter, verify there is a 5V reference at the OSS sensor pin (reference from the PCM/ECU) and a solid ground.
- Check for continuity between the sensor ground at the transmission and the PCM ground (shield or chassis ground path).
- If you have access to live data, confirm the OSS output signal changes with transmission speed and that there are no flatlines or erratic pulses.
D. Inspect the tone wheel/reluctor and internal sensor
- If you can access the transmission internals safely, inspect the OSS’s tone wheel/reluctor for damage, dirt, or misalignment.
- Check for any metallic debris or debris in the CVT that could affect sensor operation.
- Note that many CVT OSS sensors can be sensitive to mechanical wear; abnormal wear or misalignment can produce faulty readings.
E. Rule out related speed circuits
- Check for related speed-signal codes (P0500, P0715, P0721, P0722) and assess whether the issue may involve another sensor or shared circuitry (ground or power paths).
F. Consider software/ECU/TCU aspects
- If wiring and sensor integrity are confirmed, consider a software/ECU update or reflash at a Subaru dealership or qualified shop. Some cases improve after software optimization, but this is not guaranteed.
- Do not replace a PCM/TCU unless there is strong evidence of fault beyond the OSS/Wiring (e.g., failed self-test, inability to read any speed signal with proper sensor testing).
G. Functional test after repair
- Clear codes and perform a road test with speedo/cruise control verification.
- Confirm that the OSS is producing a clean, variable signal across a range of speeds and that the speedometer reads accurately.
RELATED CODES
- P0721: Output Speed Sensor Range/Performance
- P0722: Output Speed Sensor Not Achieving Expected Speed
- P0715: Input/Turbine Speed Sensor Malfunction (from the same family of speed sensor circuits)
- P0500: Vehicle Speed Sensor Malfunction (general speed sensor issue; may appear with P0720)
Note: In Subaru Outback, the OSS/VSS and related speed-sensing circuits can interplay with the PCM/TCU logic; multiple speed-sensor-related codes may appear together if there is a wiring or ground problem.
REPAIR OPTIONS AND COSTS (2025 PRICES)
Prices are rough US-range estimates; actual costs vary by region, shop rates, and parts availability.
OSS/VSS sensor replacement
- Parts: $40–$150
- Labor: 0.5–1.5 hours
- Total: roughly $120–$500
- Notes: This is often the most common fix if the sensor is faulty and wiring checks out.
Wiring harness or connectors repair/replacement (to the OSS)
- Parts: $20–$120 (if only a connector or short section needs replacement)
- Labor: 0.5–2 hours
- Total: roughly $100–$600
- Notes: If wiring is damaged or a connector is corroded, cleaning/replacing the harness segment may be sufficient.
Transmission fluid change or CVT service (addressing overall transmission health)
- Parts: $0–$60 (assuming you only replace fluid; filter change in some CVT setups may add cost)
- Labor: 0.5–1.5 hours
- Total: roughly $100–$250
- Notes: While not a direct fix for P0720, old or degraded CVT fluid can contribute to erratic sensor readings or transmission behavior. Use Subaru-recommended CVT fluid.
Software/ECU/TCU update or reflash
- Parts: typically $0–$100 (dealer or advanced shops sometimes waive diagnostic charges if a software update is performed)
- Labor: 0.5–1.5 hours
- Total: roughly $0–$300
- Notes: Some updates are offered free or under warranty campaigns; check with the dealer.
Transmission replacement or CVT replacement
- Parts: Several thousand dollars (e.g., $2,000–$6,000 for a full CVT unit in some markets)
- Labor: 6–12+ hours (depending on shop and complexity)
- Total: $4,000–$9,000+ (commonly higher in dealer settings)
- Notes: Consider this only if the OSS fault is accompanied by significant CVT mechanical failure or if multiple speed-sensor issues persist after sensor/wiring repair.
PCM/TCU replacement (rare)
- Parts: $600–$1,800
- Labor: 2–6 hours
- Total: $1,000–$3,000+
- Notes: Only after thorough fault isolation confirms PCM/TCU as the root cause.
Tips:
- Always verify failures with a second diagnostic after repairs to confirm the fault is resolved.
- When replacing the OSS, ensure the new sensor is the correct Subaru part for your specific transmission model (Outback CVT versions can vary by trim and year).
DIY vs PROFESSIONAL
- DIY viability:
- Reasonable for a competent DIYer with basic automotive electrical skills: locate OSS, inspect wiring, test with a multimeter for proper reference voltage and continuity, reseat/clean connectors, and replace the sensor if the signal is confirmed faulty.
- Tools needed: OBD-II scanner, multimeter, basic hand tools, flashlight, and the ability to safely lift and support the car if the sensor is in a difficult-to-reach area.
- Cautions: CVT transmissions and their electronics can be sensitive. If you’re unsure about wiring diagrams or how to safely access the sensor, consider professional service.
- When to go pro:
- If the OSS wiring shows damage, you’re not confident in performing electrical tests, or you suspect a PCM/TCU/software issue.
- If you don’t own the proper service manuals, torque specs, or specialized CVT knowledge.
- If the vehicle shows multiple speed-sensor related codes or the transmission is behaving abnormally beyond sensor symptoms.
PREVENTION
- Use the recommended Subaru CVT fluid and maintain proper fluid level and condition; CVT condition can influence sensor performance indirectly.
- Schedule regular maintenance checks that include transmission connectivity—inspect wiring harnesses near the transmission, especially after off-road driving or exposure to moisture.
- Avoid exposing electrical connectors to water or corrosive environments; ensure protective covers and seals are intact.
- If you notice speedometer irregularities or drivability issues, address them early to prevent potential damage to the transmission or ECU.
- Have software updates performed by an authorized dealer if Subaru issues any P0720-related reflashes or improvements.
Important data caveats
- The analysis above is based on the provided data (no recalls, no owner complaints for this exact make/model/year combination) plus general automotive knowledge about P0720 and Subaru CVT-equipped Outbacks.
- No recalls or TSBs are cited from the data you supplied.
- Costs are approximate2025 dollars and may vary by region, shop, and vehicle condition. Always confirm current pricing with your repair facility.