Fuel Level Sensor Circuit Low
The P2066 code indicates that the fuel level sensor circuit voltage is lower than expected. This typically means the sensor signal is stuck at a low voltage, often due to a short to ground, faulty sensor, or wiring issue. The powertrain control module (PCM) monitors the fuel level sensor input to determine fuel level and may trigger this code when the voltage drops below a calibrated threshold.
1. Most Common Causes
- Faulty fuel level sensor 'B' with internal short circuit causing low resistance
- Signal wire of sensor 'B' shorted to ground
- Sensor power or reference voltage wire shorted to ground
- Corroded, contaminated, or bent pins in sensor connector causing ground contact
- Internal PCM failure in signal conditioning circuit (rare)
2. Symptoms You Will Notice
- Inaccurate or erratic fuel gauge reading
- Check Engine Light illuminated
- Fuel gauge stuck on empty or full
- Possible hard start or no start if sensor affects fuel pump operation
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect fuel level sensor connector and wiring for damage, corrosion, or shorts.
Step 3: Test sensor resistance with a multimeter; compare to manufacturer specs.
Step 4: Check for voltage at sensor connector with key on; should be around 5V reference.
Step 5: If sensor and wiring check out, test PCM for proper operation.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but you may have an inaccurate fuel gauge, risking running out of fuel. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
Typically $50-$150 for a new sensor plus labor, but can vary by vehicle.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.