P0720 Code: Chevrolet Cruze (2016-2019) - Causes, Symptoms & Fixes

No recalls found in NHTSA database

Note on data used for this guide: The provided NHTSA data shows no owner complaints and no recalls for the 2016–2019 Chevrolet Cruze with P0720. That means statistical prevalence and documented recalls are not available from this dataset. The diagnostic guidance below relies on general automotive knowledge and typical OBD-II P0720 behavior for GM transmissions, applied to the Cruze’s likely 6-speed automatic transmission used in 2016–2019 models.

CODE MEANING AND SEVERITY

• Code: P0720
• Full name: Output Shaft Speed (OSS) Sensor Circuit Malfunction
• What it means: The transmission output shaft speed sensor is signaling an out-of-range, inconsistent, or missing signal to the transmission control module (TCM)/engine control module (ECM). The OSS sensor data helps the TCM regulate shifts, torque converter lockup, and overall transmission behavior.
• Where it matters: The OSS is typically mounted on or near the transmission, reading the rotation rate of the output shaft (which drives the final drive) via a tone ring or reluctor. The signal is used to coordinate upshifts, downshifts, and torque converter directives.
• Severity and drivability: Moderate to high. A P0720 can cause rough or inappropriate shifting, late or failed shifts, or the vehicle going into limp mode. In some cases the vehicle may drive in a degraded or limited manner until the fault is cleared. The transmission may also stay in a single gear or fail to shift properly, which can affect safety and drivability.
• Important: P0720 is often the first sign of OSS circuit problems, but it can also be triggered by sensor faults, wiring issues, connector corrosion, or even a faulty TCM/ECM reference circuit. It can appear alone or with related codes (e.g., P0721, P0722) that indicate sensor performance or range problems.

COMMON CAUSES ON CHEVROLET CRUZE

• Faulty Output Shaft Speed Sensor (OSS) itself
  • Sensor degraded, damaged internal electronics, or worn sensor element.
• Wiring harness fault
  • Damaged, frayed, or chafed wires in the OSS harness.
  • Poor or corroded connections at the sensor connector or at the TCM/ECM.
• Damaged or contaminated sensor connector
  • Oxidation, improper seating, bent pins, or water intrusion.
• Faulty tone ring or reluctor gear
  • Missing teeth, misalignment, damaged tone wheel, or debris interfering with the sensor’s reading.
• Transmission internal issue
  • Internal wear or debris affecting the sensor’s readout path or the output shaft assembly.
• Transmission control module (TCM) / Engine control module (ECM) reference issues
  • Faulty ground, 5V reference instability, or software/firmware glitches.
• Fluid-related factors (less common but possible)
  • Contaminated or degraded transmission fluid affecting sensor operation via electrical gremlins or thermal conditions.
• Environmental/operational factors
  • Extreme temperatures, water ingress, or high-vibration environments that degrade electrical connections over time.

SYMPTOMS

• Check Engine Light (MIL) on with P0720
• Intermittent or persistent harsh, late, or erratic shifting
• Transmission stuck in a certain gear or not upshifting/ downshifting as expected
• Slipping or flare between gears
• Erratic or inconsistent engine/vehicle speed readings in the control modules
• Possible transmission limp mode activation (limited gear range)
• No obvious external leaks; symptoms are primarily electrical/mechanical in the transaxle area
• In some cases, driving performance may feel normal until the fault is triggered again

DIAGNOSTIC STEPS

Prepare for diagnostics

• Safety first: Park on a flat surface, engage parking brake, and ensure the vehicle is in park (or neutral if performing certain tests) before inspecting components.
• Gather tools: OBD-II scan tool with live data, digital multimeter, a flashlight, service manual for Cruze or equivalent GM transmission references, and if available, an oscilloscope or scan tool capable of viewing OSS waveform.

Step-by-step diagnostic procedure

Confirm DTC details

• Retrieve all fault codes with a scan tool.
• Note any related codes (P0721, P0722, P0700, P0760, etc.). While you don’t have recalls in the dataset, related codes can indicate coupled issues (sensor performance, torque converter issues, etc.).

Verify freeze frame data and real-world conditions

• Check the conditions under which P0720 stored (engine speed, road speed, gear, transmission temp). This helps replicate and diagnose.

Visual inspection

• Inspect OSS sensor and wiring connector for signs of damage, abrasion, oil or fluid contamination, corrosion, or broken pins.
• Check the wiring harness routing for sharp edges, heat sources, or strap/routing that could cause chafing.
• Inspect the transmission area for transmission oil leaks or contamination around the sensor area.

Electrical tests on the OSS circuit

• Power and ground checks:
  • With the ignition ON (key in run position, engine OFF if recommended by manual), check the reference voltage (usually ~5V) at the OSS connector pin using a multimeter. Compare to specifications in the service manual.
  • Check the ground path to the OSS circuit; ensure a solid low-resistance ground path.
• Signal line test:
  • With the engine running (as allowed by the manual and tool), monitor the OSS signal line with a scope or a DMM; the signal should vary with engine/transmission speed. Compare to vehicle speed from the VSS/vehicle data, if possible.
• Resistance checks:
  • Measure the OSS sensor’s resistance if the service manual provides a spec. Replace the sensor if resistance is out of spec or shows abnormal behavior during movement.
• Connector integrity:
  • Disconnect and reconnect the sensor harness to reseat the connection; apply dielectric grease if recommended to reduce future corrosion.
  • Inspect for bent pins, oxidation, or debris in the connector.

Compare OSS data with vehicle speed

• Use a scan tool to view live data for OSS RPM and vehicle speed (VSS). They should correlate logically (as vehicle speed increases, OSS speed increases). If data are wildly out of sync or jumpy, the OSS or wiring is suspect, or the tone ring/readhead alignment is off.

Inspect the tone ring/reluctor assembly

• If accessible without major disassembly, inspect the tone ring or reluctor around the output shaft for damaged teeth or misalignment.
• Look for debris, metal shavings, or contamination that could cause intermittent reading.

Check for software/ECU/TCM issues

• Ensure the PCM/TCM software is up to date with GM’s latest calibrations for the Cruze. If a software update exists, it may address false readings or sensor timing.

Additional checks if symptoms persist

• If OSS and wiring test good, consider the possibility of an internal transmission issue or a faulty TCM/ECM reference circuit. A transmission teardown is typically not an immediate DIY step and requires professional evaluation.
• If the vehicle is intermittently not shifting but ultimately shifts, you may want to perform a system test with the TCM to see if it’s commanding incorrect shift points due to sensor data.

Post-repair checks

• After any replacement or repair, clear codes and perform a test drive to ensure the P0720 does not recur.
• Monitor for any new codes that could indicate cascading issues (e.g., P0700, P0750, etc.).

RELATED CODES

• P0721: Output Shaft Speed Sensor Range/Performance
  • Indicates the sensor data are out of admissible range or there is a performance issue. Often accompanies P0720 if the signal is erratic or out of spec.
• P0722 (less common): Output Shaft Speed Sensor Circuit Not Present or similar fault in some GM platforms
  • Could indicate a missing or intermittent signal path or a break in the circuit.

Note: The above related codes are commonly seen with OSS-related faults, but the exact code set can vary by year and transmission variant. In this Cruze context, P0720 can appear alone or with related codes.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Important caveats

• Prices vary by region, shop, and whether work is done at a dealership vs. independent shop.
• Labor rates for 2025 can range widely; the estimates below reflect typical ranges you might see in many U.S. markets.

A. OSS sensor replacement (quick fix if sensor is faulty)

• Parts: OSS sensor typically $40–$120
• Labor: 0.5–1.0 hour
• Estimated total: $150–$350
• Notes: If the sensor is easily accessible from the exterior of the transmission, this is a common first fix.

B. Wiring harness/connector repair

• Parts: Wiring harness segment or connector repair kit or repair sleeve; $20–$100
• Labor: 1.0–2.0 hours (depending on access)
• Estimated total: $150–$500
• Notes: If the harness is damaged or connector is corroded, this can resolve the fault without replacing the sensor.

C. Transmission fluid/service and related checks

• Fluid flush/fill (Dexron-type fluid per GM spec): $120–$250
• FCAT filter or service items if needed (varies by model)
• Estimated total: $150–$400
• Notes: While this doesn’t fix the OSS electronics directly, degraded fluid can affect transmission performance and sensor readings indirectly.

D. TCM/ECM software update or reprogramming

• Parts: None if just a software update
• Labor: 0.5–1.5 hours
• Estimated total: $100–$300 (dealer or specialized shop)
• Notes: Software updates may address calibration issues that can mimic OSS faults.

E. Transmission diagnosis that leads to internal repair

• If OSS, wiring, and software are ruled out, an internal transmission issue or a faulty pressure/valve body component could be diagnosed.
• Costs: Transmission teardown or replacement can range from $1,500 to $4,000+ depending on extent (not including possible after-treatment or labor). This is a broad range and highly dependent on the specific problem and vehicle.

F. Used/import replacement parts option

• If choosing a used OSS sensor or salvage transmission part, costs may be lower but risk reliability. Ensure you source from reputable suppliers and confirm compatibility with the Cruze’s exact transmission model.

DIY vs PROFESSIONAL

• DIY readiness:
  • Pros: If the OSS is easily accessible, you can save on labor by replacing the sensor yourself. Visual inspection of connector and wiring is straightforward.
  • Cons: Transmission electrical systems can be tricky. Access to the OSS may require undercar access, jack stands, and potentially removing covers or panels. Incorrect reassembly could cause more problems or safety concerns.
• Tools needed for DIY:
  • Basic hand tools, multimeter, and ideally a scan tool with live data or a scope for waveform observation.
  • OEM repair manual or credible online guide for torque specs and replacement procedure.
• When to seek a professional:
  • If you have intermittent symptoms, multiple DTCs, or if you need to remove transmission components or access hard-to-reach areas.
  • If a software update, reflash, or TCM/ECM diagnosis is required.
  • If the vehicle is in limp mode and you must ensure safe operation and proper repair with correct torque specs and diagnostics.
• Safety:
  • Improper testing or repair can cause electrical shock, fire risk, or unintended transmission operation. If you’re not confident, seek professional help.

PREVENTION

• Maintain transmission fluid at proper level and use the exact GM spec for Dexron fluid recommended for your Cruze’s transmission.
• Replace the transmission fluid and filter at recommended intervals; degraded or contaminated fluid can contribute to sensor and transmission issues.
• Keep electrical connections clean and tight; inspect the OSS harness and connectors for signs of corrosion, wear, or damage, especially in areas exposed to heat or road salt.
• Avoid exposure to engine bay moisture if connectors are not sealed; fix any water ingress promptly.
• Avoid aggressive driving that stresses the transmission, which can accelerate wear on sensors and the tone ring.
• If software updates are available for the Cruze’s PCM/TCM from GM, apply them to ensure calibration compatibility with OSS and related sensors.
• Regular inspections during maintenance visits can help detect sensor and wiring faults early (cracked insulation, bent pins, corrosion).

Data limitations and transparency

• Data used: The provided data indicates no NHTSA complaints and no recalls for the 2016–2019 Cruze with this code in the dataset. This limits the ability to reference real-world complaint prevalence or recall-driven fixes for this exact vehicle/year combo.
• Cited items: No recalls found in NHTSA database (per data provided). No specific TSBs are cited because the provided data does not include TSB information.
• Practical takeaway: P0720 diagnoses are typically sensor, wiring, or tone-ring-related. While this dataset doesn’t show documented recalls, the diagnostic approach and repair options described here are consistent with common industry practice for OSS-related faults in GM transmissions.