OBD-II trouble code
P0167: O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 3)
The heater inside the third oxygen sensor on Bank 2 is not behaving as commanded. Because this vehicle has two of everything downstream, the question that decides the bill is whether one heater failed or something they all share did.
Quick facts
- System
- Powertrain
- Category
- Oxygen Sensor
- Severity
- Low severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $0 – $520
- DIY difficulty
- Intermediate DIY
What does P0167 mean?
An oxygen sensor only works hot. The heater built into it is a small resistive element the controller switches on and monitors, and P0167 means the current it observed did not match what it expected when it commanded that heater at the Bank 2 Sensor 3 position.
What makes this code worth thinking about rather than simply acting on is the hardware count. A vehicle that has a third sensor on a second bank has at least six oxygen sensors, and on some configurations more. Every one of them has a heater, and those heaters are not independent — they are typically fed from a shared fused supply, sometimes through a common relay, and they frequently share ground points. That architecture means a single fuse, a single relay contact or a single corroded ground can produce heater codes on several sensors at once, and it means the honest first move is to read every code in memory before ordering anything.
The arithmetic is stark. If P0167 is the only heater code stored, one sensor is the likely answer and the repair is one part. If P0167 arrives with P0147, or with heater codes at other positions, the probability that several independent heaters failed simultaneously is very low compared with the probability that their shared feed did. That is a fuse, a relay or a ground stud — often under fifty dollars and sometimes nothing at all — versus a stack of sensors that will not fix the problem. Nobody should approve multiple oxygen sensors on a vehicle like this until the shared supply has been measured.
The second cost consideration is what happens to the quote when someone suggests replacing all the sensors as preventive maintenance. On a typical four-sensor car that is a manageable figure. On a six-plus sensor vehicle with a position-specific rear sensor that is not stocked by most parts counters, the same sentence describes a much larger bill. Replace the one that failed.
As for consequences, a dead heater at this position does not affect how the engine runs. It does mean the element may never reach operating temperature at all, because at the tail end of an exhaust behind two converters there is not enough residual heat to sustain it. That silences the sensor permanently rather than for the first two minutes, which is why heater codes here tend to arrive with slow-response or no-activity codes as companions describing the same single fault.
Common causes
- Open heater element inside the sensor
- Blown fuse or failed relay in a supply shared by several oxygen sensor heaters
- Corroded shared ground point serving the rear sensor heaters
- Broken or chafed heater supply or ground wire on the long bank 2 run
- Water intrusion and corrosion in the sensor connector
- Control driver in the engine control module failed for that circuit
- Incorrect replacement sensor with a heater resistance outside the expected range
Symptoms
- Check engine light on with no change in how the vehicle drives
- Slow-response or no-activity codes for the same sensor stored alongside
- Heater codes present at more than one sensor position
- Catalyst and oxygen sensor monitors will not complete
- Emissions inspection rejected on the stored code or incomplete monitors
Diagnostic steps
- 1.Read every code in memory before ordering parts. Heater codes at more than one position point at a shared fuse, relay or ground rather than at multiple failed sensors.
- 2.Check the fuse and relay feeding the oxygen sensor heaters, and locate the shared ground point for the rear sensors. Clean and retest before anything is condemned.
- 3.Measure heater resistance at the sensor connector and compare against the specification for the vehicle. An open reading confirms a failed element.
- 4.Confirm the heater supply arrives at the connector with the key on and that the control side switches as commanded.
- 5.Perform a voltage drop test on the heater supply and ground with the heater drawing current. The bank 2 legs are the long ones and resistance shows up only under load.
- 6.Inspect the connector for water and corrosion, which is common at the most rearward sensor position on the vehicle.
- 7.If slow-response or no-activity codes are stored for the same sensor, treat them as consequences of the heater fault and re-evaluate only after the heater is working.
Repair cost
$0 – $520
A blown fuse or a cleaned ground can cost almost nothing and resolves several codes at once. Relay replacement typically runs $20 to $90. Wiring repair on the bank 2 legs runs $80 to $300. Sensor replacement is roughly $190 to $520 fitted. Be cautious of any quote to replace all oxygen sensors on this vehicle — it has at least six, and the figure is much larger than the same suggestion on an ordinary car.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with oxygen sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.