P0167 OBD2 Code Guide
P0167 is a powertrain diagnostic trouble code. Use this hub to understand the plain meaning, the first checks to run, and which vehicle-specific guides may be more useful before replacing parts.
O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 3)
Code P0167 indicates a specific issue with the heater circuit of the third oxygen sensor located on Bank 2. Bank 2 typically refers to the cylinder bank that does not contain cylinder #1 (e.g., passenger side on most V6/V8 engines). Sensor 3 is the post-catalytic converter sensor, primarily responsible for monitoring the efficiency of the catalytic converter. The heater circuit is crucial for bringing the O2 sensor to its operating temperature quickly, allowing it to provide accurate readings to the Powertrain Control Module (PCM) for emissions control and fuel trim adjustments. A malfunction means the PCM is not detecting the expected electrical resistance or current flow in this heater circuit, preventing the sensor from reaching optimal operating temperature or functioning correctly.
Code verification standard
P0167 is published with SAE J2012 / ISO 15031-6 code structure plus OBD2 P0167 diagnostic context.
First checks
- - Read all stored and pending codes before clearing anything.
- - Save freeze-frame data so you know speed, load and temperature when the code set.
- - Inspect wiring, connectors, fuses, hoses and obvious leaks tied to the named system.
- - Compare live data against realistic values before buying sensors or modules.
- - Clear the code only after repair and complete a drive cycle to confirm it does not return.
P0167 diagnostic path
- 1Visual Inspection: Begin by visually inspecting the Bank 2, Sensor 3 O2 sensor, its wiring harness, and connectors for any signs of damage, corrosion, fraying, or loose connections. Pay close attention to areas where wiring might rub against hot exhaust components or sharp edges.
- 2Check Heater Circuit Power and Ground: Disconnect the O2 sensor connector. Using a multimeter, check for battery voltage (B+) at the power supply wire for the heater circuit and a good ground connection at the ground wire, with the ignition ON (engine OFF). Consult a wiring diagram for the correct pin assignments.
- 3Measure Heater Element Resistance: With the O2 sensor connector still disconnected, measure the resistance across the two heater circuit terminals on the O2 sensor itself (not the vehicle harness side). Compare this reading to manufacturer specifications. An open circuit (infinite resistance) or a reading significantly outside the specified range indicates an internal sensor heater failure.
- 4Inspect Wiring Continuity to PCM: If power and ground are present at the connector and the sensor's heater resistance is within spec, check for continuity and resistance in the wiring from the O2 sensor connector back to the PCM. Look for high resistance or open circuits in both the power and ground wires leading to the PCM.
- 5Advanced Scan Tool Diagnostics: If available, use a professional scan tool to monitor live data for the O2 sensor heater circuit. Some vehicles allow monitoring of heater current draw or commanded duty cycle, which can help pinpoint if the PCM is attempting to activate the heater but failing to see a response.
Verify before repair
- - Replace the O2 Sensor (Bank 2, Sensor 3): The most common fix is replacing the faulty oxygen sensor, as the heater element often fails internally.
- - Repair or Replace Damaged Wiring/Connectors: Address any frayed, corroded, or broken wires and connectors in the O2 sensor heater circuit.
- - Check and Replace Blown Fuses: Inspect any fuses related to the O2 sensor heater circuit, as a blown fuse can cut off power to the heater.
- - Diagnose/Replace Powertrain Control Module (PCM): In rare cases, the PCM's driver circuit for the O2 sensor heater may be faulty, requiring repair or replacement of the PCM.
Vehicle-specific pages to check next
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