P0147 O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 3

P0147 points to a heater circuit malfunction on bank 1 sensor 3. The heater used to bring the downstream sensor online is faulty.

Code details

Generic OBD-II · P0

System: Fuel / Air
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace emissions components before confirming heater power and ground at bank 1 sensor 3.

Symptoms of P0147

Check-engine light on, sometimes with rough or uneven running.
Hesitation, surging, or a noticeable change in fuel economy.
Occasionally hard starting or a smell of unburnt fuel.

Common causes of P0147

A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
Wiring, connector, or fuel-delivery problems that skew the reading.

Useful checks before replacing parts

Check bank 1 sensor 3 heater feed voltage, ground or driver control, resistance, current draw, fuse supply, and connector condition.
Inspect wiring near exhaust heat, melted insulation, loose terminals, connector corrosion, and shared oxygen sensor heater circuits.
Compare heater command with sensor warm-up time, readiness monitor status, and related heater circuit codes.

Related OBD-II codes

These nearby fuel / air entries can help compare wording and pin down the fault area.