P0167 Code: O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 3)
Note: We do not currently have verified model-specific diagnostic data for the Buick Envision. The symptoms and fixes listed below are the standard generic OBD2 guidelines for the P0167 code. Always consult a factory service manual before replacing parts.
What does this mean?
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.
How serious is this code?
While not an immediate safety hazard, a malfunctioning O2 sensor heater circuit can lead to increased exhaust emissions, reduced fuel efficiency, and potentially cause other related diagnostic trouble codes over time. It's advisable to address the issue promptly to maintain optimal engine performance and environmental compliance.
Diagnostic system: General powertrain circuit
On a Buick Envision, the P0167 code should be diagnosed as part of the general powertrain circuit group. Related codes and live data from this same system can change the repair priority, so avoid replacing parts from the code name alone.
Most Common Causes for Buick Envision
- Faulty oxygen (O2) sensor
- Failed O2 sensor heater circuit
- Damaged, chafed, or broken wiring harness
- Exhaust leak before oxygen sensor
Symptoms to Watch For
- Check Engine Light is illuminated
- Decreased fuel economy
- Failed emissions test
Before replacing parts, check these first
- Record freeze-frame data and related codes before clearing the fault.
- Inspect wiring, connectors, vacuum lines, fluid leaks, and fuses tied to the named system.
- Use live data or a multimeter to confirm the failed circuit before replacing parts.
- Check for blown fuses, weak battery voltage, and damaged connectors before buying major parts.
Live data to compare
- Freeze-frame conditions
- Related codes
- Circuit voltage and continuity
How to Diagnose
Common Mistakes
Treating the code description as a parts list instead of verifying the circuit, operating conditions, and related codes. Always confirm the fault with freeze-frame data, live data, visual inspection, and circuit checks before spending money on parts.
Repair verification
After the repair, clear P0167, complete a drive cycle, and confirm the monitor runs without the code returning. Save the before/after scan report if the vehicle needs emissions inspection.
Frequently Asked Questions
Can I drive with the P0167 code?
If the check engine light is solid, you can usually drive to a safe location or mechanic. If the light is flashing, pull over immediately to prevent catastrophic engine or catalytic converter damage.
Will the P0167 code clear itself?
Once the underlying problem is fixed, the engine computer will run its self-checks. If it passes over several drive cycles, the light will turn off automatically. You can also clear it immediately using an OBD2 scanner.
Will this code fail an emissions test?
Yes. If the Check Engine Light is on due to the P0167 code, your Buick will automatically fail an OBD2 plug-in emissions or smog test.
What should I check first for P0167?
Record freeze-frame data and related codes before clearing the fault. Inspect wiring, connectors, vacuum lines, fluid leaks, and fuses tied to the named system. Use live data or a multimeter to confirm the failed circuit before replacing parts.
Join the Discussion
Repair Estimate
Fuse, connector, wiring, cleaning, or basic inspection
Major component replacement after live data and circuit tests confirm failure
Costs vary widely; start with visual inspection and circuit confirmation to avoid unnecessary parts.
DIY Difficulty
Can usually be performed at home with basic hand tools.