P0720 Code: Dodge Charger (2021-2023) - Causes, Symptoms & Fixes

Below is a comprehensive diagnostic guide for P0720 (Output Speed Sensor Malfunction / Transmission Output Sensor Circuit) as it applies to 2021–2023 Dodge Charger. Important data note: No recalls found in NHTSA database for this make/model/year/issue, and the provided dataset shows no owner complaints for this exact code. This guide combines the general meaning of P0720 with typical Charger specifics, plus practical diagnostics. Data limitations: the entry states “No recalls found in NHTSA database” and “No NHTSA complaints found” for this combination, so this guide relies on general automotive knowledge and common P0720 fault patterns rather than model-specific NHTSA trouble reports.

CODE MEANING AND SEVERITY

• What P0720 means: P0720 is the diagnostic trouble code for an Output Speed Sensor (OSS) circuit malfunction. The OSS (often referred to as Output Shaft Speed Sensor in many transmissions) provides the transmission controller with the actual output shaft speed. When the PCM/TCM detects an implausible, out-of-range, or missing OSS signal, it sets P0720.
• Severity and impact on the Charger: Moderate to potentially major. If the OSS data is lost or out of spec, the transmission may not shift correctly, may go into fail-safe/limp mode, or the gauge cluster (speedometer) may read incorrectly. You may notice harsh or incorrect shifts, or the vehicle may not move properly in some situations. In some cases, the vehicle may run reasonably well until shifting decisions rely on the OSS data, after which drivability is affected.
• Typical related codes you might see with OSS issues: P0721 (OSS range/performance), P0722 (OSS circuit no signal), P0715 (Input/Turbine Speed Sensor issues) and P0730 (Incorrect gear ratio) depending on the interface with the TCM/PCM. Exact pairings depend on the vehicle’s software and how the fault manifests.

COMMON CAUSES ON DODGE CHARGER

• Faulty Output Shaft Speed Sensor (OSS) or its wiring: a failing sensor, damaged sensor connector, corroded pins, or a displaced sensor.
• Damaged or degraded wiring harness between the OSS and the PCM/TCM: cracked insulation, pin loosening, harness chafing, or exposure to moisture/ salt.
• Poor electrical reference: bad ground or degraded 5V reference (the OSS typically uses a regulated reference from the PCM/TCM).
• Transmission electronics or calibration: PCM/TCM software calibration issues or a defective transmission control module.
• Mechanical transmission issue masquerading as OSS fault: worn gears, internal transmission damage, or an issue causing irregular shaft speeds.
• Connector/earth/ground issues near the OSS path or inside the transmission harness.
• Aftermarket modifications: non-factory tuning or altered wiring can affect sensor signals or calibration.

SYMPTOMS

• Check Engine Light (MIL) with code P0720.
• Erratic or harsh/shuddering shifts, especially between gears or at certain RPM ranges.
• Transmission may go into limp mode or fail-safe, limiting the available gears.
• Speedometer reading may be inaccurate or erratic if the OSS data is not being read correctly.
• Cruise control may behave erratically or disengage unexpectedly.
• In some cases, the vehicle may feel drivable but with hesitation, unwillingness to move until the gear is manually selected, or unusual sound/vibration during shifting.

DIAGNOSTIC STEPS

Note: Start with basic electrical checks and avoid replacing parts without confirming the fault.

• Step 1: Verify the code and check for other codes

  • Use a professional-grade scan tool to confirm P0720 and check for related/combined codes (P0721–P0724 family, P0715, P0730, etc.).
  • Check for pending codes and freeze-frame data to understand conditions when the fault occurred.

• Step 2: Visually inspect the OSS circuit and wiring

  • Locate the OSS at the transmission output area (often near the rear of the transmission or on a related output shaft housing, depending on the exact 8-speed design used in your Charger).
  • Inspect the sensor, its connector, and the wire harness for signs of damage, corrosion, oil leaks, heat damage, or moisture entry.
  • Check that connectors are fully seated and pins are not bent or corroded.

• Step 3: Test electrical references and sensor signals (live data)

  • With a good scan tool, monitor OSS signal live data, vehicle speed (VSS), and engine RPM while the car is stationary and during a road test.
  • Confirm there is a proper 5V reference and a solid ground for the OSS circuit. A poor ground or a weak reference can trigger P0720.
  • Look for a plausible relationship between engine RPM and OSS data. If engine RPM changes but OSS data remains constant or reads zero, that can indicate a faulty sensor or a broken circuit.

• Step 4: Electrical checks with a multimeter (if you’re comfortable)

  • Disconnect the OSS connector.
  • Check resistance/continuity of the OSS wires from the connector to the sensor; look for opens or short to ground.
  • If the OSS is three-wire (power, ground, signal), verify the supply voltage (within spec), signal output, and ground continuity. A stuck or fluctuating signal supports a sensor or wiring fault.
  • Check the battery’s ground strap and chassis ground near the transmission for cleanliness and tightness.

• Step 5: Sensor swap/bench test (if a known-good spare is available)

  • If you have access to a known-good OSS sensor for the Charger, swap it in to determine if the fault clears.
  • After replacement, clear codes and perform a road test to verify that the OSS signal is now read correctly and the code does not return.

• Step 6: Inspect for mechanical causes

  • Ensure the transmission output shaft can rotate freely by hand where safe (not always practical with transmission in vehicle, but check for any obvious mechanical binding or abnormal noises during service).
  • Consider transmission fluid condition and level. While P0720 is speed-sensor related, extremely degraded or contaminated fluid can contribute to slippage and shifting irregularities that aggravate sensor readings.

• Step 7: Recheck and test drive

  • After any repair or component swap, clear DTCs, perform a test drive across various speeds and loads, and re-scan to confirm the code does not reappear.

• Step 8: Software and calibration considerations

  • If the sensor and wiring check out, but the fault persists, discuss with a dealer or qualified shop about PCM/TCM software calibration or updates. Note: this guide follows the data constraint of no cited TSBs in the provided dataset; software updates would be considered a next step if suggested by a dealer and not guaranteed by a specific TSB.

RELATED CODES

• P0721, P0722, P0723, P0724 (codes in the same OSS family related to speed sensor range, signal, or circuit). Some vehicles may also show P0715 (Input/Turbine Speed Sensor) or P0730 (Incorrect gear ratio) if the transmission is interpreting speed data incorrectly. The exact codes appearing with P0720 can vary by vehicle software and conditions.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Prices are rough estimates and vary by region, shop, and vehicle configuration.

• OSS sensor replacement

  • Parts: typically $15–$120
  • Labor: about 0.5–1.0 hours
  • Estimated total: $100–$320

• Wiring harness/connector repair or replacement

  • Parts: often minimal unless harness replacement is needed
  • Labor: 1.0–2.5 hours
  • Estimated total: $150–$500

• PCM/TCM software updates or calibration (dealer or specialized shop)

  • Parts/Software: often included in service; diagnostic/testing time can be $0–$150
  • Estimated total: $0–$150 (depends on dealer/program availability)

• Transmission internal issues (if OSS fault is not the root cause)

  • Rebuild or replacement of transmission or valve body may be required
  • Estimated total: $2,000–$6,000+ (varies widely by model, extent of damage, and labor)

• Additional ancillary repairs

  • Sealing, mounting, or related harness repairs if water ingress or corrosion is found
  • Estimated total: $50–$300 depending on parts and labor

DIY vs PROFESSIONAL

• DIY-friendly aspects

  • Visual inspection of the OSS sensor and its wiring
  • Basic electrical checks (continuity and resistance) if you have a reliable multimeter and experience
  • Replacing the OSS sensor if it is easily accessible and you’re comfortable with under-vehicle work
  • Important: Disconnect the battery before working on electrical components; ensure the vehicle is securely supported; refer to the service manual for torque specs and safety cautions.

• DIY limitations

  • The OSS sensor location and accessibility can vary by Charger trim and transmission type; in some vehicles, sensor replacement may require certain components to be removed or access panels to be removed.

• When to call a professional

  • If you’re not comfortable with electrical diagnostics, wiring harness checks, or transmission-related work
  • If the OSS sensor and wiring appear intact but the fault persists
  • If the transmission is exhibiting hard shifts, limp mode, or internal mechanical concerns that require transmission service or rebuild

PREVENTION

• Regular maintenance and attention to transmission fluid
  • Use the manufacturer’s recommended transmission fluid specification and maintain proper fluid level and condition. Contaminated or low fluid can contribute to misbehavior in transmission sensors and actuation.
• Electrical connector care
  • Keep sensor connectors clean and dry; use dielectric grease on connector seals to resist moisture intrusion
• Avoid harsh driving conditions that stress the transmission
  • Quick, harsh shifts, aggressive acceleration, or consistently pushing transmission limits can exacerbate sensor and valve body wear
• Park and storage considerations
  • When parked in damp environments, ensure the underbody area around the transmission is protected from pooling water or road salt, which can corrode connectors
• Prevent leaks
  • Address engine or transmission oil leaks promptly. Leaks near the OSS wiring can lead to short circuits or corrosion over time
• Monitor sensor health
  • Periodically scan for DTCs and address any OSS-related codes promptly to prevent potential driveability issues from escalating

DATA LIMITATIONS AND FINAL NOTES

• The provided dataset indicates: No recalls found in NHTSA database for this make/model/year/issue, and No NHTSA complaints found for P0720 in 2021–2023 Charger as per the data you provided.
• This guide uses general P0720 knowledge and common Charger transmission practices to outline diagnostic steps, possible causes, and typical repair options. Individual vehicles may differ, and model-year/trim specifics can affect sensor placement and service procedures.
• If you pursue repairs yourself, ensure you have the proper safety equipment, service manuals, and torque specifications. If in doubt, consult or hire a qualified automotive technician.