No recalls found in NHTSA database
Real NHTSA data provided for Chevrolet Silverado (2019-2024) shows no owner complaints and no recalls for this issue. The diagnostic guide below uses general automotive knowledge for P0720 (Output Shaft Speed Sensor Circuit Malfunction) as it applies to Silverado models in this year range, with notes about data limitations from the provided dataset.
CODE MEANING AND SEVERITY
- What the code means: P0720 = Output Shaft Speed Sensor Circuit Malfunction. This indicates a problem with the sensor that monitors the transmission’s output shaft speed (often used by the PCM/TCM to manage shift timing and to provide vehicle speed data to the gauge cluster and other systems).
- Why it matters: The PCM/TCM relies on a valid output shaft speed signal to control transmission shift points, torque conversion, and speedometer accuracy. A faulty or intermittent signal can cause incorrect shifting, erratic speedometer readings, or even temporary loss of drive in some circumstances.
- Severity on Silverado: Moderate. In many cases you’ll notice shifting abnormalities, a malfunctioning or inoperative speedometer, or a check engine light. Depending on the fault, a vehicle may enter a fail-safe/limp mode to protect the transmission and drivability. Since the data shows no reported recalls or complaints in the supplied dataset, treat this as a potentially intermittent sensor/wiring issue that warrants inspection.
COMMON CAUSES ON CHEVROLET SILVERADO
- Faulty or failed output shaft speed sensor itself
- Damaged, worn, or corroded sensor connector or wiring harness (looms, pins, or insulation)
- Wiring shorts, opens, or chafing between the sensor and the PCM/TCM
- Loose or poorly connected sensor harness
- Faulty ground or battery/auxiliary power issues affecting sensor signal conditioning
- Transmission speed signal relays or PCM/TCM fault causing misinterpretation of the sensor data
- Problem with the tone ring/reluctor wheel or mechanical misalignment (sensor reads a degraded or erratic signal)
- Contaminated or degraded transmission fluid or incorrect fluid level (in some cases can affect sensor reading indirectly via transmission control)
- Software/calibration issues in the TCM or PCM (less common but possible; may be addressed in service bulletins)
SYMPTOMS
- Speedometer reads wrong, fluctuates, or goes blank
- Transmission shifts late, erratically, or harshly; possible reluctance to upshift or downshift
- Vehicle may enter limp mode or rough/shuddering shifts
- Check Engine Light (CEL) or transmission warning light illuminated
- Driving may feel “off” at highway speeds or during acceleration
- In some cases, cruise control speed may not match actual vehicle speed if VSS signal is lost or erratic
- Scanning the vehicle reveals P0720 and possibly related VSS (Vehicle Speed Sensor) related codes (e.g., P0721–P0724 in many platforms)
DIAGNOSTIC STEPS
Note: Begin with a scan to confirm P0720 and note any related codes. Use the vehicle’s OEM service information as your primary reference when available.
Step 1: Confirm and document
- Read all stored and pending codes with a quality scan tool.
- Record freeze-frame data and any IVS/TCM data related to the transmission and vehicle speed.
Step 2: Visual inspection
- Inspect the output shaft speed sensor and its connector for looseness, damage, corrosion, or bent pins.
- Check the wiring harness for chafing, scrapes, or exposed conductors along the route from the sensor to the PCM/TCM.
- Inspect grounds and power supply connections for the sensor circuit; look for corrosion or loose grounds.
Step 3: Sensor testing (sensor and circuit)
-With the ignition on, test the sensor’s electrical resistance (per OEM spec) and compare to the expected range. If the resistance is out of spec or data shows no signal, the sensor is suspect.- Perform a resistance/continuity check on the wiring harness from the sensor to the PCM/TCM connector.
- Check for short to ground or to power on the sensor circuit.
- If available, use an oscilloscope or a data-logger to observe the sensor’s output waveform while driving at various speeds. Look for a clean, repeatable signal; look for dropout, noise, or irregular waveform.
Step 4: Sensor location and signal integrity
- Identify whether the sensor is mounted on the transmission tailshaft or near the output shaft; ensure the reluctor tone ring (reluctor) aligns and isn’t damaged.
- Inspect the tone ring for chips, cracks, or misalignment; a damaged tone ring can produce inconsistent signals.
Step 5: Vehicle speed signal path
- Verify the vehicle speed signal being used by the PCM/TCM and instrument cluster is derived from the VSS. If another vehicle speed signal source is present (e.g., ABS wheel speeds), confirm there isn’t a fault cross-talking or mixed signals.
Step 6: Transmission Fluid and external factors
- Check transmission fluid level and condition. Low or contaminated fluid can contribute to sensor signal integrity issues in some cases.
- Ensure there are no coolant or fluid leaks affecting electrical connectors.
Step 7: Test drive and data correlation
- After performing repairs or replacements, erase codes and drive under varying loads and speeds.
- Re-scan to confirm the P0720 is cleared and that the sensor data shows a valid, consistent speed signal.
- Monitor for any related codes (P0721–P0724 or P0700 family codes) that can indicate secondary issues.
Step 8: Advanced or professional steps
- If the sensor and wiring appear intact and the issue persists, consider PCM/TCM inspection, reprogramming, or updating software per OEM service information.
- In cases where the tone ring or transmission internal components are suspected, professional disassembly and inspection may be required.
RELATED CODES
- P0721 – Output Shaft Speed Sensor Circuit Range/Performance (or similar range/quality fault in the same family)
- P0722 – Output Shaft Speed Sensor Circuit No Signal (varies by market; may indicate a complete loss of signal)
- P0723 – Output Shaft Speed Sensor Circuit Intermittent or Erratic signal
- P0724 – Other variations of the Output Shaft Speed Sensor Circuit faults
- Note: The P0720 family is often accompanied by other transmission control codes (e.g., P0700) if the PCM/TCM detects multiple transmission faults.
REPAIR OPTIONS AND COSTS (2025 PRICES)
Prices can vary by region, shop, and whether the Silverado uses a 6L80, 8L90, 10-speed, or other transmission. The figures below are general averages to help planning.
Output Shaft Speed Sensor replacement
- Parts: typically $20–$120
- Labor: typically 0.5–2 hours depending on access
- Estimated total: $150–$350
Wiring harness/connector repair or replacement
- Parts: $20–$200 (depending on whether you replace a simple connector or a larger harness segment)
- Labor: $60–$200
- Estimated total: $100–$400
Sensor and wiring combination (sensor replaced and wiring re-sealed/relocated)
- Parts: $30–$150
- Labor: $100–$250
- Estimated total: $130–$400
Transmission internal issues affecting the sensor signal (tone ring, sensor mount, or mechanical concerns)
- Parts: $50–$300 for replacement components
- Labor: $150–$450
- Estimated total: $200–$750
PCM/TCM software update or reprogramming
- Parts: typically $0–$150 if a software file is provided by the dealer/tech
- Labor: $100–$250
- Estimated total: $100–$400
Full transmission service or replacement (if the fault is symptomatic of broader transmission problems)
- Parts: $1,000–$4,000 (new or remanufactured transmission varies by model and configuration)
- Labor: $500–$1800
- Estimated total: $1,500–$5,800+ (prices can be higher for certain models or specialty configurations)
Notes on pricing:
- These ranges reflect typical independent shops and dealer-quoted ranges in 2025 dollars. Local labor rates and parts sourcing will affect final numbers.
- If the issue is solely a sensor or wiring fault, costs are on the lower end. If the problem is found to be internal to the transmission or requires a software reflash, costs rise accordingly.
DIY vs PROFESSIONAL
- DIY-friendly tasks (with appropriate tools and caution):
- Visual inspection of sensor and harness; cleaning connector terminals and reseating connectors (with the battery disconnected).
- Basic electrical tests: resistance/continuity checks in the sensor circuit; voltage checks with ignition on to confirm supply and ground presence.
- Checking for obvious wiring damage or chafing and fixing or shielding as needed.
- Tasks better left to professionals:
- Accessing the sensor if it’s difficult to reach without removal of major components.
- Using an oscilloscope or advanced data-logging to evaluate the signal waveform and for diagnosing intermittent faults.
- Replacing the sensor and testing with drive cycles and data logging to confirm a clean signal under real-world conditions.
- Transmission-related work (tone ring, internal sensor alignment, or PCM/TCM reprogramming) typically requires specialized tools and knowledge; often best handled by a trained technician.
PREVENTION
- Regularly inspect the transmission electrical connectors and harnesses for signs of wear or corrosion; fix exposed wiring promptly.
- Maintain proper transmission fluid level and use the correct specification for the Silverado. Replace fluid per the manufacturer’s recommended maintenance schedule to keep hydraulic and sensor environments clean.
- Avoid prolonged exposure to moisture, salt, or contaminated roads; wash underbody areas as needed to reduce corrosion risk on connectors.
- If you notice intermittent electrical symptoms (e.g., flickering gauges or occasional shifts), address them early before the problem escalates to a complete sensor failure.
- When performing repairs, ensure you clear fault codes and perform a proper test drive to verify the issue is resolved and not intermittent.
Important data limitations note
- The provided dataset for this request indicates no NHTSA owner complaints and no recalls for the 2019–2024 Silverado with this issue. No official recalls are listed in the data. Therefore, this guide emphasizes general diagnostic and repair practices for P0720 based on common automotive knowledge and typical industry procedures, rather than documented NHTSA complaints or recalls specific to this model/year. If you have access to OEM service bulletins or dealer advisories, consult them for model-specific steps or revised repair procedures.