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DTC codes / P01xx · Fuel and air metering / P0167

P0167O2 Sensor Heater Circuit (Bank 2 Sensor 3)

P0167 indicates that the powertrain control module has detected a fault in the heater circuit for the downstream oxygen sensor on bank 2, which is the side of the engine that does not contain cylinder number one. The heater is responsible for bringing the sensor up to operating temperature quickly so the engine can enter closed-loop fuel control sooner after a cold start.

SystemPowertrain
Code typeGeneric (all makes)
SeverityLow
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • A slight decrease in fuel economy because the sensor may stay in open-loop longer than normal.
  • Occasional rough idle or hesitation during cold starts if the sensor does not heat up properly.
  • In some cases, a failed emissions test due to the sensor not being ready.
  • Rarely, a rich or lean condition may develop if the sensor heater failure affects the sensor's signal accuracy.

Common causes, most likely first

  1. Open or shorted heating element inside the bank 2 sensor 3 oxygen sensor.
  2. Damaged or corroded wiring or connector at the sensor or along the circuit.
  3. Blown fuse that supplies power to the oxygen sensor heater circuit.
  4. Faulty oxygen sensor heater relay, if the vehicle uses one.
  5. Poor ground connection for the heater circuit.
  6. Failed powertrain control module driver for the heater circuit, though this is uncommon.

How to diagnose and fix it

  1. Check the fuse that protects the oxygen sensor heater circuit and replace it if blown.
  2. Inspect the wiring and connector at the bank 2 sensor 3 for damage, corrosion, or loose pins; repair as needed.
  3. Measure the resistance of the heater element in the sensor; compare to the manufacturer's specification and replace the sensor if out of range.
  4. Test for power and ground at the sensor connector with the key on; if power or ground is missing, trace the circuit back to the relay or fuse box.
  5. If the circuit tests good, check the heater control signal from the powertrain control module; a faulty driver may require module repair or replacement.
  6. Clear the diagnostic trouble code and verify the repair by running the appropriate monitor; ensure the code does not return.

What the heater circuit code really means

  • A P0167 code often sets because the heater element inside the sensor has simply worn out, but a corroded connector can mimic the same failure and is frequently overlooked.
  • The downstream sensor on bank 2 is sometimes misidentified as the primary sensor, leading to replacement of the wrong part; always confirm bank and sensor location in the service information.
  • A blown fuse for the oxygen sensor heater circuit can be caused by a shorted sensor or wiring, so replacing the fuse without finding the short will lead to a repeat failure.
  • The heater circuit is only active during cold starts and for a short period afterward, so a fault may not be present during a warm-engine test; a cold-soak test is often necessary to reproduce the issue.
  • Some vehicles use a single relay to power multiple oxygen sensor heaters, so a failure in that relay can set codes for several sensors at once, not just P0167.

Can I keep driving with P0167?

You can generally continue driving with this code because the engine will still run, but the vehicle may not enter closed-loop fuel control as quickly, which can slightly increase fuel consumption and emissions. Avoid prolonged idling and schedule a diagnosis soon to prevent potential damage to the catalytic converter from a rich condition.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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