If your OBD-II scanner displays P0167, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected an electrical problem affecting the heater circuit for the Bank 2 Sensor 3 oxygen (O2) sensor.
The generic OBD-II definition for P0167 is:
O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3)
Bank 2 Sensor 3 is the third oxygen sensor located on the engine bank that does not contain cylinder number one. On vehicles equipped with multiple catalytic converters and three oxygen sensors per bank, this sensor is typically installed after the secondary catalytic converter.
Unlike upstream oxygen sensors that directly influence fuel delivery, Bank 2 Sensor 3 primarily monitors secondary catalytic converter efficiency and long-term emissions system performance.
The built-in heater allows the sensor to reach operating temperature quickly so the PCM can begin emissions monitoring without waiting for exhaust heat alone.
The PCM uses the Bank 2 Sensor 3 heater circuit to:
- Warm the oxygen sensor rapidly
- Enable secondary catalyst monitoring
- Reduce cold-start emissions
- Complete OBD-II readiness monitors
- Improve emissions system accuracy
When the PCM detects incorrect resistance, excessive current, insufficient current, an open circuit, or a short within the heater circuit, it stores P0167 and usually illuminates the Check Engine Light.
Common causes include:
- Failed oxygen sensor heater element
- Open heater circuit
- Shorted heater wiring
- Blown heater fuse
- Failed heater relay
- Connector corrosion
- Poor ground connection
- PCM faults (rare)
Unlike P0166, which indicates no oxygen sensor activity, P0167 specifically identifies a malfunction in the electrical heater circuit for Bank 2 Sensor 3.
What Does the P0167 Code Mean?
Modern oxygen sensors require high temperatures before they can accurately measure oxygen levels in the exhaust stream.
A zirconia oxygen sensor typically begins operating correctly at approximately:
- 600°F–650°F (315°C–343°C)
To reduce warm-up time, manufacturers install an electric heating element inside the sensor.
The heater circuit usually includes:
- Battery voltage supply
- Fuse protection
- Relay control on some vehicles
- PCM-controlled power or ground
- Internal heater element
If the PCM detects that the heater circuit is not operating within specifications, it stores P0167.
The code does not automatically mean the sensing element itself has failed.
Where Is Bank 2 Sensor 3 Located?
Bank 2 Sensor 3 is generally mounted after the secondary catalytic converter on the cylinder bank opposite cylinder number one.
On vehicles equipped with three oxygen sensors per bank:
- Sensor 1 — Before the catalytic converter
- Sensor 2 — After the primary catalytic converter
- Sensor 3 — After the secondary catalytic converter
Not all vehicles use a third oxygen sensor, making P0167 considerably less common than many earlier oxygen sensor codes.
Always verify the location using the vehicle’s factory service information before testing or replacing anything. Apparently, guessing which sensor is which remains a popular and expensive diagnostic technique.
Bank 2 Sensor 1 vs. Sensor 2 vs. Sensor 3
Understanding oxygen sensor locations helps prevent replacing the wrong component.
Bank 2 Sensor 1
Located before the catalytic converter.
Responsible for:
- Air-fuel ratio monitoring
- Fuel trim adjustments
- Closed-loop fuel control
- Engine performance
Bank 2 Sensor 2
Located after the primary catalytic converter.
Responsible for:
- Primary catalyst efficiency monitoring
- Emissions verification
- Catalyst readiness monitoring
Bank 2 Sensor 3
Located after the secondary catalytic converter.
Responsible for:
- Secondary catalyst monitoring
- Long-term emissions verification
- Secondary catalyst readiness
- Overall emissions system evaluation
Because Sensor 3 does not directly control fuel delivery, P0167 usually causes little or no noticeable drivability problems.
How the Oxygen Sensor Heater Works
The heater element is a small electrical resistor built into the oxygen sensor.
When the engine starts:
- Battery voltage is supplied to the heater circuit.
- The PCM activates or regulates the heater.
- The internal heating element warms the sensor.
- The sensor reaches operating temperature quickly.
- Secondary catalyst monitoring begins sooner.
Depending on the vehicle, the PCM may control:
- Heater ground
- Heater power
- Pulse-width-modulated duty cycle
- Current flow
The exact circuit design varies by manufacturer.
What Does “Heater Circuit Malfunction” Mean?
A heater circuit malfunction means the PCM has detected an electrical condition outside the expected range.
Possible problems include:
- Open heater element
- Shorted heater element
- Open power wire
- Open ground wire
- Short to ground
- Short to battery voltage
- Excessive circuit resistance
- Blown fuse
- Failed relay
- PCM driver failure
The fault may exist inside the oxygen sensor or elsewhere in the heater circuit.
How the PCM Detects P0167
The PCM may monitor:
- Heater resistance
- Heater current draw
- Heater voltage
- Circuit continuity
- Sensor warm-up time
- Commanded heater operation
P0167 may be stored if the PCM detects:
- No current flow
- Excessive current
- Incorrect resistance
- Delayed sensor warm-up
- Open or shorted circuit
Some vehicles detect the fault immediately after startup, while others require one or more complete drive cycles.
Why the Heater Circuit Is Important
A properly functioning oxygen sensor heater allows emissions monitoring to begin much sooner.
Benefits include:
- Faster sensor activation
- Reduced cold-start emissions
- Faster catalyst monitor completion
- Improved OBD-II readiness
- More accurate emissions diagnostics
Without the heater, the sensor may eventually warm through exhaust heat, but readiness monitoring may be delayed or prevented entirely.
Can a Bad Oxygen Sensor Cause P0167?
Yes.
The heater is built into the oxygen sensor assembly, so an internally failed heater usually requires replacement of the complete sensor.
Typical internal failures include:
- Burned-out heater element
- Internal open circuit
- Internal short circuit
- Heat-related damage
- Moisture intrusion
- Age-related deterioration
Resistance testing can often confirm an internally failed heater.
Can a Blown Fuse Cause P0167?
Absolutely.
Many oxygen sensor heater circuits share a fuse with:
- Other oxygen sensor heaters
- Air-fuel ratio sensor heaters
- Emissions control devices
- Engine management relays
A blown fuse may cause P0167 along with several additional heater circuit codes.
Never replace a blown fuse and declare victory without checking why it failed. Fuses rarely sacrifice themselves for personal growth.
Can Wiring Problems Cause P0167?
Yes.
Common wiring faults include:
- Broken heater wires
- Melted insulation
- Chafed wiring
- Shorted conductors
- Corroded terminals
- Loose connectors
- Poor grounds
- Rodent damage
Because Bank 2 Sensor 3 is located near the exhaust system, heat damage and improper harness routing are especially common concerns.
P0167 Quick Facts
| Item | Information |
|---|---|
| DTC | P0167 |
| Generic Definition | O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3) |
| System | Fuel and Emissions |
| Sensor Location | Bank 2 Sensor 3 |
| Severity | Low to Moderate |
| Safe to Drive? | Usually |
| Common Symptoms | Check Engine Light, delayed readiness monitors, failed emissions inspection |
| Common Causes | Failed heater element, blown fuse, damaged wiring, connector corrosion |
| Typical Repair Cost | $100–700+ |
| Related Codes | P0162, P0163, P0164, P0165, P0166 |
Common Vehicles That Experience P0167
P0167 may appear on certain vehicles from:
- Ford
- Chevrolet
- GMC
- Toyota
- Lexus
- Nissan
- Infiniti
- BMW
- Mercedes-Benz
- Volkswagen
- Audi
The code is limited to vehicles equipped with a Bank 2 Sensor 3 heated oxygen sensor, so application varies significantly.
What Does P0167 Really Mean?
The wording of P0167 often causes drivers to assume the entire oxygen sensor has stopped working.
The code does not automatically mean:
- The sensing element has failed.
- The catalytic converter is defective.
- The engine is running rich or lean.
- The PCM must be replaced.
Instead, it means the PCM has detected an electrical malfunction in the heater circuit for the Bank 2 Sensor 3 oxygen sensor.
The fault may involve:
- Internal heater element
- Heater power wire
- Heater ground wire
- Fuse
- Relay
- Electrical connector
- PCM driver
Think of P0167 as the PCM saying:
“The heater for the third oxygen sensor on Bank 2 is not operating correctly. I need the heater circuit tested so the sensor can warm up and monitor the secondary catalytic converter properly.”
Common P0167 Scan Tool Patterns
Monitoring live scan-tool data is one of the fastest ways to diagnose P0167.
Unlike P0162 through P0166, which focus on oxygen sensor signal problems, P0167 specifically indicates an electrical malfunction within the heater circuit for Bank 2 Sensor 3.
Professional scan tools allow technicians to monitor heater command status, current draw, voltage supply, oxygen sensor warm-up time, catalyst monitor operation, and heater readiness to determine whether the problem is caused by a failed heater element, blown fuse, damaged wiring, poor ground, relay failure, or PCM issue.
Pattern 1: Heater Commanded ON but No Current Flow
The most common scan-tool pattern is:
- Heater commanded ON
- Zero current draw
- Sensor remains cold
- Delayed sensor activation
Possible causes include:
- Open heater element
- Blown fuse
- Broken heater wire
- Failed relay
- Open circuit
Pattern 2: Heater Current Too High
Some vehicles monitor heater current directly.
The scan tool may display:
- Excessive current draw
- Heater overload
- Heater short circuit
Possible causes include:
- Shorted heater element
- Short to ground
- Internal oxygen sensor failure
- Damaged wiring
Pattern 3: Slow Sensor Warm-Up
Monitor:
- Oxygen sensor temperature
- Heater status
- Oxygen sensor activity
Common observations include:
- Delayed sensor operation
- Slow catalyst monitor completion
- Extended warm-up period
Possible causes include:
- Weak heater element
- High circuit resistance
- Low charging voltage
- Aging oxygen sensor
Pattern 4: Other Oxygen Sensors Operate Normally
Compare:
- Bank 2 Sensor 1
- Bank 2 Sensor 2
- Bank 2 Sensor 3
If:
- Sensors 1 and 2 warm up normally
- Sensor 3 heater fails
The problem is usually isolated to the Bank 2 Sensor 3 heater circuit.
Comparing heater performance helps eliminate vehicle-wide charging or power supply problems.
Pattern 5: Heater Circuit Works Intermittently
Some scan tools show:
- Heater cycling on and off
- Intermittent heater current
- Unstable voltage supply
Possible causes include:
- Loose connector
- Broken wiring
- Corroded terminals
- Intermittent relay failure
Harness movement testing often reproduces this fault.
Pattern 6: Multiple Heater Circuit Codes
P0167 may appear with:
- P0036
- P0056
- P0141
- P0161
This usually indicates:
- Blown heater fuse
- Shared power supply failure
- Relay malfunction
- Common wiring problem
When several heater circuit codes appear together, inspect shared circuits before replacing sensors.
Common Symptoms of P0167
Because Bank 2 Sensor 3 primarily monitors emissions, drivability symptoms are usually minimal.
Common symptoms include:
- Check Engine Light
- Failed emissions inspection
- Delayed catalyst monitor completion
- Oxygen sensor readiness monitor incomplete
- Increased cold-start emissions
- Extended emissions monitor warm-up
- Secondary catalyst monitor incomplete
- Intermittent Check Engine Light
- Usually no noticeable engine performance problems
- Rare reduction in fuel economy
Many drivers notice nothing beyond the illuminated Check Engine Light.
Check Engine Light
The Check Engine Light is typically the first symptom.
Most manufacturers require:
- Heater circuit malfunction
- Failed self-tests
- Proper operating conditions
before storing P0167.
Failed Emissions Inspection
P0167 commonly causes emissions failures because:
- The Check Engine Light is illuminated.
- Oxygen sensor readiness remains incomplete.
- Catalyst monitor cannot complete.
- OBD-II readiness testing fails.
Even if the vehicle drives normally, emissions compliance may be impossible until repairs are completed.
Increased Cold-Start Emissions
Without a functioning heater:
- The oxygen sensor takes longer to reach operating temperature.
- Catalyst monitoring is delayed.
- Cold-start emissions increase.
- Readiness monitors require more drive time.
Slight Fuel Economy Changes
Although uncommon, some vehicles may experience:
- Slight reduction in fuel economy
- Longer open-loop operation after startup
Because Sensor 3 does not directly control fuel delivery, fuel economy changes are usually minimal.
Is P0167 Serious?
P0167 is generally considered a low-to-moderate severity diagnostic trouble code.
Most vehicles remain safe to drive.
However, delaying repairs may eventually result in:
- Failed emissions testing
- Delayed readiness monitors
- Increased cold-start emissions
- Reduced emissions monitoring accuracy
Repairs should be completed before emissions testing.
Can You Drive With P0167?
Yes.
Driving is generally safe if:
- The engine runs normally.
- The Check Engine Light is not flashing.
- No severe catalyst-related codes are present.
Repairs should be scheduled promptly if:
- Emissions testing is required.
- Additional oxygen sensor codes appear.
- Readiness monitors remain incomplete.
- Heater-related faults continue returning.
P0167 vs Related Trouble Codes
Understanding related Bank 2 Sensor 3 codes simplifies diagnosis.
P0162
O2 Sensor Circuit Malfunction (Bank 2 Sensor 3)
General electrical fault affecting the oxygen sensor circuit.
P0163
O2 Sensor Circuit Low Voltage (Bank 2 Sensor 3)
The oxygen sensor voltage remains below manufacturer specifications.
P0164
O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
The oxygen sensor voltage remains above manufacturer specifications.
P0165
O2 Sensor Circuit Slow Response (Bank 2 Sensor 3)
The oxygen sensor reacts slower than expected.
P0166
O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 3)
The PCM detects no usable oxygen sensor signal.
P0167
O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3)
The PCM detects an electrical fault within the oxygen sensor heater circuit.
30 Common Causes of P0167
The most common causes include:
- Failed heater element
- Open heater circuit
- Shorted heater circuit
- Blown heater fuse
- Failed heater relay
- Broken heater wiring
- Melted wiring insulation
- Connector corrosion
- Loose electrical connector
- Poor ground connection
- High circuit resistance
- Low battery voltage
- Charging system problems
- Heat-damaged wiring
- Rodent damage
- Moisture intrusion
- Burned connector terminals
- Previous wiring repairs
- Incorrect replacement oxygen sensor
- Damaged PCM connector
- Shared heater circuit failure
- Short to battery voltage
- Short to ground
- Internal oxygen sensor damage
- Harness routing damage
- Loose fuse connection
- PCM software issue
- Internal PCM driver fault
- Low-quality aftermarket oxygen sensor
- PCM failure (rare)
Final Thoughts
The P0167 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3) code indicates the PCM has detected an electrical fault affecting the heater circuit of the third oxygen sensor on Bank 2. While a failed heater element is the most common cause, blown fuses, failed relays, damaged wiring, connector corrosion, poor grounds, charging system problems, and electrical shorts can all trigger this code.
Proper diagnosis should determine whether the fault originates in:
- Bank 2 Sensor 3 heater element
- Heater wiring
- Fuse
- Relay
- Electrical connector
- Ground circuit
- PCM
The next section of this guide covers:
- Complete diagnostic procedures
- Heater resistance testing
- Voltage and current testing
- Fuse and relay inspection
- Repair procedures
- Repair costs
- Manufacturer-specific troubleshooting
Following a structured diagnostic process prevents unnecessary oxygen sensor replacement while restoring proper heater operation, emissions readiness, and accurate secondary catalyst monitoring.
Related Pro Street Diagnostic Guides
- P0162 – O2 Sensor Circuit Malfunction (Bank 2 Sensor 3)
- P0163 – O2 Sensor Circuit Low Voltage (Bank 2 Sensor 3)
- P0164 – O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
- P0165 – O2 Sensor Circuit Slow Response (Bank 2 Sensor 3)
- P0166 – O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 3)
- P0161 – O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
How to Diagnose the P0167 Code
Diagnosing P0167 requires determining why the PCM has detected a malfunction in the Bank 2 Sensor 3 oxygen sensor heater circuit.
Unlike P0162 through P0166, which primarily involve oxygen sensor signal problems, P0167 specifically points to an electrical fault within the heater circuit that warms the sensor to operating temperature.
The heater circuit malfunction may be caused by:
- Failed heater element
- Open heater circuit
- Shorted heater circuit
- Blown fuse
- Failed relay
- Damaged wiring
- Connector corrosion
- Poor ground
- PCM issues (rare)
Proper diagnosis should determine whether the fault originates in the oxygen sensor heater, wiring, fuse, relay, PCM driver, or power supply before replacing expensive components.
Safety Precautions
Before beginning diagnosis:
- Park the vehicle on level ground.
- Set the parking brake.
- Allow the exhaust system to cool completely.
- Wear safety glasses.
- Wear insulated gloves.
- Disconnect the battery before repairing electrical wiring.
Bank 2 Sensor 3 is normally mounted near the secondary catalytic converter where temperatures frequently exceed 800°F (425°C).
Tools Required
Professional diagnosis may require:
- Professional scan tool
- Live-data capability
- Digital multimeter
- Digital storage oscilloscope (optional)
- Oxygen sensor socket
- Back-probe test leads
- Wiring diagrams
- Test light
- Infrared thermometer
- Basic hand tools
A quality digital multimeter is the most important tool for diagnosing heater circuit faults.
Step 1 – Verify the Code
Connect a professional scan tool.
Record:
- Stored DTCs
- Pending DTCs
- Permanent DTCs
- Freeze-frame data
Monitor:
- Heater command status
- Oxygen sensor voltage
- Battery voltage
- Coolant temperature
- Engine RPM
Always record freeze-frame data before clearing diagnostic trouble codes.
Step 2 – Check for Related Trouble Codes
P0167 commonly appears with:
- P0162
- P0163
- P0164
- P0165
- P0166
- P0036
- P0056
- P0141
- P0161
Related heater circuit codes often simplify diagnosis.
| Code Combination | Likely Diagnosis |
|---|---|
| P0167 only | Heater element or wiring fault |
| P0167 + P0161 | Shared heater circuit problem |
| Multiple heater circuit codes | Blown fuse or relay failure |
| P0167 + P0166 | Sensor heater and signal fault |
| Multiple oxygen sensor codes | Shared power supply or PCM issue |
Repair shared electrical problems before replacing individual sensors.
Step 3 – Monitor Heater Operation
Using live scan data, monitor:
- Heater ON/OFF command
- Heater duty cycle (if available)
- Oxygen sensor warm-up time
Normal operation:
- Heater activates shortly after startup
- Sensor reaches operating temperature quickly
- Readiness monitors begin normally
Abnormal operation:
- Heater never activates
- Delayed warm-up
- Heater fault reported
- No current flow
Step 4 – Inspect the Oxygen Sensor
Inspect Bank 2 Sensor 3 for:
- Physical damage
- Heat damage
- Cracked housing
- Loose installation
- Melted connector
- Burned wiring
Internal heater damage often accompanies external heat damage.
Step 5 – Inspect the Electrical Connector
Disconnect the oxygen sensor connector.
Inspect for:
- Corrosion
- Bent terminals
- Loose pins
- Moisture intrusion
- Burned contacts
- Broken locking tabs
Poor electrical connections commonly interrupt heater circuit operation.
Step 6 – Inspect the Wiring Harness
Inspect wiring between the oxygen sensor and PCM.
Look for:
- Broken heater wires
- Melted insulation
- Chafed wiring
- Exhaust heat damage
- Rodent damage
- Previous repair damage
The heater wiring often carries more current than the sensor signal wires and is more susceptible to heat damage.
Step 7 – Check the Heater Fuse
Locate the oxygen sensor heater fuse.
Inspect for:
- Blown fuse
- Loose fuse connection
- Corroded fuse terminals
If the fuse is blown:
- Do not simply replace it.
- Determine why the fuse failed before restoring power.
Repeated fuse failures usually indicate a short circuit.
Step 8 – Test Heater Resistance
Disconnect the oxygen sensor.
Using a digital multimeter:
Measure resistance across the heater terminals.
Compare the reading to manufacturer specifications.
Possible results:
- Infinite resistance → Open heater element
- Very low resistance → Shorted heater element
- Within specification → Heater likely functional
An internally open heater element is one of the most common causes of P0167.
Step 9 – Verify Heater Power Supply
Turn the ignition ON.
Measure:
- Battery voltage at the heater connector
- Voltage supplied from the fuse
- Relay output (if equipped)
No voltage indicates:
- Blown fuse
- Failed relay
- Broken wiring
- PCM control issue
Step 10 – Verify Ground Integrity
Inspect the heater ground circuit.
Measure:
- Ground resistance
- Voltage drop
Inspect for:
- Loose grounds
- Corrosion
- Broken ground wires
Poor grounds reduce heater performance and frequently trigger P0167.
Step 11 – Test Circuit Continuity
Measure continuity between:
- Oxygen sensor connector
- Fuse
- Relay
- PCM connector
Inspect for:
- Open circuits
- High resistance
- Damaged conductors
Repair continuity problems before replacing components.
Step 12 – Test for Shorts
Inspect the heater circuit for:
- Short to battery voltage
- Short to ground
- Short between heater wires
Electrical shorts commonly damage heater circuits and repeatedly blow fuses.
Step 13 – Inspect the Heater Relay
If equipped:
Inspect:
- Relay contacts
- Relay output
- Relay coil resistance
- Relay operation
Swap with a known-good relay when possible to verify operation.
Step 14 – Review Technical Service Bulletins
Before replacing expensive components:
Review manufacturer Technical Service Bulletins (TSBs).
Look for:
- Heater circuit updates
- PCM calibration revisions
- Wiring harness improvements
- Connector redesigns
Some manufacturers have released updated heater circuit strategies.
Step 15 – Review Freeze-Frame Data
Compare current operating conditions with freeze-frame information.
Review:
- Coolant temperature
- Engine RPM
- Vehicle speed
- Battery voltage
- Heater command status
Freeze-frame data often identifies the exact conditions that triggered P0167.
Step 16 – Verify Charging System Voltage
Measure charging voltage.
Normal charging voltage should remain between:
- 13.5–14.8 volts
Low charging voltage may reduce heater performance.
High charging voltage can damage heater elements.
Step 17 – Inspect PCM Connector Integrity
Inspect PCM connectors for:
- Corrosion
- Bent terminals
- Moisture intrusion
- Loose pins
- Damaged locks
Poor PCM connections can interrupt heater circuit control.
Step 18 – Inspect Previous Repairs
Inspect for:
- Incorrect oxygen sensor installation
- Low-quality aftermarket sensors
- Poor wiring repairs
- Harness rerouting
- Exhaust modifications
Improper repairs frequently contribute to heater circuit failures.
Step 19 – Confirm Heater Operation After Repairs
If repairs have already been performed:
Monitor:
- Heater activation
- Warm-up time
- Oxygen sensor readiness
- Current draw
Verify the heater now operates normally.
Step 20 – Confirm the Diagnosis
Before replacing any major component, verify:
- Heater element resistance
- Fuse condition
- Relay operation
- Wiring continuity
- Power supply
- Ground integrity
- Charging system voltage
- PCM software level
Completing these diagnostic steps prevents unnecessary oxygen sensor replacement while accurately identifying the root cause of P0167.
Step 21 – Replace the Bank 2 Sensor 3 Oxygen Sensor
If testing confirms the heater element inside the Bank 2 Sensor 3 oxygen sensor has failed, replacement of the complete sensor is the proper repair.
General replacement procedure:
- Allow the exhaust system to cool completely.
- Disconnect the oxygen sensor electrical connector.
- Remove the sensor using an oxygen sensor socket.
- Inspect the sensor threads and catalytic converter bung.
- Install an OEM or high-quality replacement heated oxygen sensor.
- Tighten the sensor to the manufacturer’s specified torque.
- Reconnect the electrical connector.
- Clear all diagnostic trouble codes.
- Verify proper heater operation with a professional scan tool.
OEM oxygen sensors typically provide more accurate heater resistance values, faster warm-up times, and greater long-term reliability than inexpensive aftermarket replacements.
Step 22 – Repair Heater Circuit Wiring
Inspect the complete Bank 2 Sensor 3 heater wiring harness.
Repair:
- Broken heater wires
- Melted insulation
- Chafed wiring
- Exhaust heat damage
- Damaged wire splices
- Rodent damage
Heater circuit wiring carries higher current than the signal circuit and is especially vulnerable to heat damage near the exhaust system.
Step 23 – Replace Damaged Connectors
Inspect the oxygen sensor connector.
Repair or replace:
- Corroded terminals
- Bent connector pins
- Loose terminals
- Moisture-damaged connectors
- Burned electrical contacts
- Broken locking tabs
Poor connector integrity frequently interrupts heater circuit operation and causes intermittent faults.
Step 24 – Repair Ground Circuit Problems
Inspect:
- Engine grounds
- Chassis grounds
- Heater circuit grounds
- Ground eyelets
Measure:
- Ground resistance
- Voltage drop under load
A poor ground increases heater circuit resistance and may prevent the oxygen sensor from reaching operating temperature.
Step 25 – Replace Blown Heater Fuse
Locate the heater circuit fuse.
Inspect for:
- Blown fuse
- Loose fuse terminals
- Corrosion
- Overheated fuse holder
If the fuse has failed:
- Replace it with the correct amperage.
- Immediately investigate why it failed.
Repeated fuse failures usually indicate a short-to-ground or internally shorted heater element.
Step 26 – Replace a Faulty Heater Relay
If the vehicle uses a dedicated heater relay:
Inspect:
- Relay contacts
- Relay coil resistance
- Voltage output
- Relay activation
Replace the relay if testing confirms improper operation.
A failed relay can prevent power from reaching multiple oxygen sensor heaters.
Step 27 – Repair Short Circuits or Open Circuits
Using wiring diagrams and a multimeter:
Inspect for:
- Short to battery voltage
- Short to ground
- Open heater circuit
- High-resistance wiring
- Damaged conductors
Repair all wiring faults before replacing additional components.
Step 28 – Update PCM Software
Before replacing the PCM:
Review manufacturer Technical Service Bulletins (TSBs).
Manufacturers occasionally release software updates addressing:
- False P0167 detection
- Heater circuit diagnostics
- Emissions monitor strategies
- Oxygen sensor warm-up logic
- PCM calibration revisions
Always verify the PCM contains the latest available software.
Step 29 – Verify Heater Operation
After repairs:
Monitor:
- Heater command
- Heater current (if supported)
- Oxygen sensor warm-up time
- Oxygen sensor activity
- Catalyst monitor
- Oxygen sensor readiness monitor
A properly functioning heater should rapidly warm the sensor, allowing emissions monitoring to begin shortly after startup.
Step 30 – Consider PCM Failure
PCM failure is extremely uncommon.
Only suspect the PCM after confirming:
- Heater element integrity
- Fuse condition
- Relay operation
- Wiring continuity
- Power supply
- Ground quality
- Charging system voltage
- PCM software updates
PCM replacement should always be the final diagnostic step.
How to Fix P0167
The proper repair depends entirely on the diagnostic results.
Common repairs include:
- Replacing Bank 2 Sensor 3 oxygen sensor
- Repairing heater circuit wiring
- Replacing damaged connectors
- Repairing poor grounds
- Replacing a blown fuse
- Replacing a faulty relay
- Repairing open circuits
- Repairing short circuits
- Updating PCM software
- Replacing the PCM (rare)
Verifying the Repair
After completing repairs:
- Clear all diagnostic trouble codes.
- Start the engine from a cold condition.
- Monitor heater activation.
- Verify rapid oxygen sensor warm-up.
- Confirm oxygen sensor activity begins normally.
- Complete a full drive cycle.
- Verify oxygen sensor and catalyst readiness monitors complete.
- Confirm no pending or permanent DTCs return.
- Perform a final scan to verify a successful repair.
A successful repair restores proper heater operation, accurate secondary catalyst monitoring, reduced cold-start emissions, and complete OBD-II readiness.
Typical Repair Costs
| Repair | Typical Cost |
|---|---|
| Professional diagnosis | $100–250 |
| Bank 2 Sensor 3 replacement | $175–500 |
| Heater wiring repair | $100–400 |
| Open or short circuit repair | $100–350 |
| Connector replacement | $100–300 |
| Ground circuit repair | $100–250 |
| Heater fuse replacement | $10–75 |
| Heater relay replacement | $50–200 |
| PCM software update | $100–250 |
| Battery replacement | $150–350 |
| Alternator replacement | $400–1,000 |
| PCM replacement | $800–2,000+ |
Repair costs vary depending on vehicle design, labor rates, oxygen sensor accessibility, and the underlying cause of the heater circuit malfunction.
Common Diagnostic Mistakes
Avoid these common mistakes:
- Replacing the oxygen sensor before checking the heater fuse
- Ignoring relay operation
- Overlooking connector corrosion
- Failing to measure heater resistance
- Skipping voltage drop testing
- Clearing codes before recording freeze-frame data
- Ignoring Technical Service Bulletins
- Replacing the catalytic converter before diagnosing the heater circuit
- Replacing the PCM before verifying the complete electrical system
Many P0167 repairs involve correcting fuse, relay, wiring, or connector problems rather than replacing the oxygen sensor.
Manufacturer-Specific Notes
Ford
Inspect:
- Heater wiring
- Heater fuse
- Relay operation
- Connector corrosion
Heat-damaged wiring is a common cause of P0167 on Ford applications.
General Motors (Chevrolet/GMC)
Verify:
- Heater current
- Wiring continuity
- Fuse integrity
- PCM connector condition
Shared heater power circuits commonly contribute to P0167.
Toyota/Lexus
Inspect:
- Heater resistance
- Connector condition
- Wiring continuity
- PCM calibration
Toyota factory scan tools provide enhanced heater circuit diagnostics.
Honda/Acura
Inspect:
- Electrical connectors
- Ground quality
- Heater power supply
- Harness routing
Connector corrosion and damaged wiring commonly cause heater circuit faults.
Nissan/Infiniti
Verify:
- Heater wiring
- Exhaust heat shielding
- Fuse condition
- Harness integrity
High exhaust temperatures frequently damage downstream heater wiring.
BMW/Mercedes-Benz
Inspect:
- Heater activation
- Current draw
- Wiring continuity
- Secondary catalyst readiness
Factory diagnostic software provides detailed heater circuit testing.
Hyundai/Kia
Inspect:
- Connector corrosion
- Moisture intrusion
- Heater wiring
- Ground integrity
Electrical connector failures are common causes of P0167.
Frequently Asked Questions
What usually fixes P0167?
The most common repairs include replacing the Bank 2 Sensor 3 oxygen sensor, repairing heater wiring, replacing a blown fuse or faulty relay, repairing damaged connectors, repairing poor grounds, or updating PCM software.
Can I drive with P0167?
Yes. Most vehicles remain drivable, but repairs should be completed before emissions testing because P0167 commonly prevents oxygen sensor and catalyst readiness monitors from completing.
Does P0167 always mean the oxygen sensor is bad?
No. Blown fuses, faulty relays, damaged wiring, connector corrosion, poor grounds, and open heater circuits can all trigger P0167 without requiring oxygen sensor replacement.
Can a blown fuse cause P0167?
Yes. A blown heater circuit fuse is a common cause of P0167, especially when multiple oxygen sensor heater circuit codes are stored simultaneously.
Can P0167 cause a failed emissions inspection?
Yes. Because the heater circuit affects oxygen sensor warm-up and catalyst monitoring, P0167 commonly prevents OBD-II readiness monitors from completing and usually results in an emissions inspection failure.
Is P0167 a serious code?
P0167 is generally considered a low-to-moderate severity diagnostic trouble code. While it rarely affects drivability, it can delay oxygen sensor warm-up, increase cold-start emissions, interrupt catalyst monitoring, and prevent emissions compliance if left unrepaired.
Final Thoughts
The P0167 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3) code indicates the PCM has detected an electrical fault affecting the heater circuit of the third oxygen sensor on Bank 2. While a failed heater element is a common cause, blown fuses, faulty relays, damaged wiring, connector corrosion, poor grounds, electrical shorts, and PCM-related issues can all prevent the heater from operating correctly.
A complete diagnosis should always verify:
- Heater element resistance
- Fuse condition
- Relay operation
- Wiring continuity
- Power supply
- Ground quality
- Charging system voltage
- PCM software level
Following a structured diagnostic process prevents unnecessary parts replacement while restoring rapid oxygen sensor warm-up, accurate secondary catalyst monitoring, emissions compliance, and complete OBD-II readiness.
Continue Your Pro Street Bank 2 Sensor 3 Series
Related guides include:
- P0162 – O2 Sensor Circuit Malfunction (Bank 2 Sensor 3)
- P0163 – O2 Sensor Circuit Low Voltage (Bank 2 Sensor 3)
- P0164 – O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
- P0165 – O2 Sensor Circuit Slow Response (Bank 2 Sensor 3)
- P0166 – O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 3)
- P0161 – O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
