P0143: O2 Sensor Circuit Low Voltage Bank 1 Sensor 3

Severity

Medium

System

Fuel and Air Metering

Last reviewed: Jan 1, 0001 Last updated: Jan 1, 0001

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What Does P0143 Mean?

P0143 is a diagnostic trouble code indicating: O2 Sensor Circuit Low Voltage Bank 1 Sensor 3. This code relates to the fuel and air metering system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P0143

⚠️ Check Engine Light (MIL) illuminated
⚠️ O2 Sensor reading at zero or minimum value
⚠️ Related system not functioning or in fail-safe mode
⚠️ Poor fuel economy

Common Causes

🔍 Open or broken wire in O2 Sensor circuit
🔍 Poor ground connection at O2 Sensor
🔍 Faulty O2 Sensor with no output signal
🔍 Disconnected or loose O2 Sensor connector
🔍 Blown fuse in related circuit

Frequently Asked Questions

What does P0143 mean?

P0143 indicates: O2 Sensor Circuit Low Voltage Bank 1 Sensor 3. The vehicle's computer has detected that the O2 Sensor is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P0143?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P0143 for extended periods may cause additional problems.

How much does it cost to fix P0143?

Repair costs for P0143 typically range from $20 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Repair broken wire or restore ground in O2 Sensor circuit
🔧 Clean and secure O2 Sensor connector and ground points
🔧 Replace failed O2 Sensor

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

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