Output Speed Sensor Circuit Malfunction
The P0720 code indicates a malfunction in the output speed sensor circuit, which monitors the transmission's output shaft speed. This sensor provides critical data to the powertrain control module (PCM) for shift timing and torque converter lockup. A fault can cause erratic shifting, limp mode, or transmission damage.
01. Most Common Causes
- Faulty output speed sensor
- Damaged wiring or connector
- Low transmission fluid level
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Erratic or harsh shifting
- Transmission stuck in limp mode
- Speedometer inoperative or inaccurate
03. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P0720 is present.
Step 2: Inspect output speed sensor wiring and connector for damage or corrosion.
Step 3: Test sensor resistance and voltage output with a multimeter.
Step 4: Check transmission fluid level and condition.
Step 5: If sensor and wiring are good, inspect tone wheel or internal transmission components.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with P0720 can cause erratic shifting, transmission damage, or sudden loss of drive. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for sensor replacement, but costs can be higher if wiring repairs or internal transmission work is needed.