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P0167 Code Explained: O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3) Causes, Symptoms & Fixes

P0167 code illustration showing the Bank 2 Sensor 3 heated oxygen sensor, heater circuit warning, fuse, relay, Check Engine Light, Pro Street TV logo, and www.ProStreetOnline.com.

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:

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:

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:

To reduce warm-up time, manufacturers install an electric heating element inside the sensor.

The heater circuit usually includes:

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:

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:

Bank 2 Sensor 2

Located after the primary catalytic converter.

Responsible for:

Bank 2 Sensor 3

Located after the secondary catalytic converter.

Responsible for:

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:

  1. Battery voltage is supplied to the heater circuit.
  2. The PCM activates or regulates the heater.
  3. The internal heating element warms the sensor.
  4. The sensor reaches operating temperature quickly.
  5. Secondary catalyst monitoring begins sooner.

Depending on the vehicle, the PCM may control:

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:

The fault may exist inside the oxygen sensor or elsewhere in the heater circuit.

How the PCM Detects P0167

The PCM may monitor:

P0167 may be stored if the PCM detects:

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:

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:

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:

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:

Because Bank 2 Sensor 3 is located near the exhaust system, heat damage and improper harness routing are especially common concerns.

P0167 Quick Facts

ItemInformation
DTCP0167
Generic DefinitionO2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 3)
SystemFuel and Emissions
Sensor LocationBank 2 Sensor 3
SeverityLow to Moderate
Safe to Drive?Usually
Common SymptomsCheck Engine Light, delayed readiness monitors, failed emissions inspection
Common CausesFailed heater element, blown fuse, damaged wiring, connector corrosion
Typical Repair Cost$100–700+
Related CodesP0162, P0163, P0164, P0165, P0166

Common Vehicles That Experience P0167

P0167 may appear on certain vehicles from:

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:

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:

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:

Possible causes include:

Pattern 2: Heater Current Too High

Some vehicles monitor heater current directly.

The scan tool may display:

Possible causes include:

Pattern 3: Slow Sensor Warm-Up

Monitor:

Common observations include:

Possible causes include:

Pattern 4: Other Oxygen Sensors Operate Normally

Compare:

If:

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:

Possible causes include:

Harness movement testing often reproduces this fault.

Pattern 6: Multiple Heater Circuit Codes

P0167 may appear with:

This usually indicates:

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:

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:

before storing P0167.

Failed Emissions Inspection

P0167 commonly causes emissions failures because:

Even if the vehicle drives normally, emissions compliance may be impossible until repairs are completed.

Increased Cold-Start Emissions

Without a functioning heater:

Slight Fuel Economy Changes

Although uncommon, some vehicles may experience:

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:

Repairs should be completed before emissions testing.

Can You Drive With P0167?

Yes.

Driving is generally safe if:

Repairs should be scheduled promptly if:

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:

  1. Failed heater element
  2. Open heater circuit
  3. Shorted heater circuit
  4. Blown heater fuse
  5. Failed heater relay
  6. Broken heater wiring
  7. Melted wiring insulation
  8. Connector corrosion
  9. Loose electrical connector
  10. Poor ground connection
  11. High circuit resistance
  12. Low battery voltage
  13. Charging system problems
  14. Heat-damaged wiring
  15. Rodent damage
  16. Moisture intrusion
  17. Burned connector terminals
  18. Previous wiring repairs
  19. Incorrect replacement oxygen sensor
  20. Damaged PCM connector
  21. Shared heater circuit failure
  22. Short to battery voltage
  23. Short to ground
  24. Internal oxygen sensor damage
  25. Harness routing damage
  26. Loose fuse connection
  27. PCM software issue
  28. Internal PCM driver fault
  29. Low-quality aftermarket oxygen sensor
  30. 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:

The next section of this guide covers:

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

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:

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:

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:

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:

Monitor:

Always record freeze-frame data before clearing diagnostic trouble codes.

Step 2 – Check for Related Trouble Codes

P0167 commonly appears with:

Related heater circuit codes often simplify diagnosis.

Code CombinationLikely Diagnosis
P0167 onlyHeater element or wiring fault
P0167 + P0161Shared heater circuit problem
Multiple heater circuit codesBlown fuse or relay failure
P0167 + P0166Sensor heater and signal fault
Multiple oxygen sensor codesShared power supply or PCM issue

Repair shared electrical problems before replacing individual sensors.

Step 3 – Monitor Heater Operation

Using live scan data, monitor:

Normal operation:

Abnormal operation:

Step 4 – Inspect the Oxygen Sensor

Inspect Bank 2 Sensor 3 for:

Internal heater damage often accompanies external heat damage.

Step 5 – Inspect the Electrical Connector

Disconnect the oxygen sensor connector.

Inspect for:

Poor electrical connections commonly interrupt heater circuit operation.

Step 6 – Inspect the Wiring Harness

Inspect wiring between the oxygen sensor and PCM.

Look for:

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:

If the fuse is blown:

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:

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:

No voltage indicates:

Step 10 – Verify Ground Integrity

Inspect the heater ground circuit.

Measure:

Inspect for:

Poor grounds reduce heater performance and frequently trigger P0167.

Step 11 – Test Circuit Continuity

Measure continuity between:

Inspect for:

Repair continuity problems before replacing components.

Step 12 – Test for Shorts

Inspect the heater circuit for:

Electrical shorts commonly damage heater circuits and repeatedly blow fuses.

Step 13 – Inspect the Heater Relay

If equipped:

Inspect:

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:

Some manufacturers have released updated heater circuit strategies.

Step 15 – Review Freeze-Frame Data

Compare current operating conditions with freeze-frame information.

Review:

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:

Low charging voltage may reduce heater performance.

High charging voltage can damage heater elements.

Step 17 – Inspect PCM Connector Integrity

Inspect PCM connectors for:

Poor PCM connections can interrupt heater circuit control.

Step 18 – Inspect Previous Repairs

Inspect for:

Improper repairs frequently contribute to heater circuit failures.

Step 19 – Confirm Heater Operation After Repairs

If repairs have already been performed:

Monitor:

Verify the heater now operates normally.

Step 20 – Confirm the Diagnosis

Before replacing any major component, verify:

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:

  1. Allow the exhaust system to cool completely.
  2. Disconnect the oxygen sensor electrical connector.
  3. Remove the sensor using an oxygen sensor socket.
  4. Inspect the sensor threads and catalytic converter bung.
  5. Install an OEM or high-quality replacement heated oxygen sensor.
  6. Tighten the sensor to the manufacturer’s specified torque.
  7. Reconnect the electrical connector.
  8. Clear all diagnostic trouble codes.
  9. 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:

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:

Poor connector integrity frequently interrupts heater circuit operation and causes intermittent faults.

Step 24 – Repair Ground Circuit Problems

Inspect:

Measure:

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:

If the fuse has 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:

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:

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:

Always verify the PCM contains the latest available software.

Step 29 – Verify Heater Operation

After repairs:

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:

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:

Verifying the Repair

After completing repairs:

  1. Clear all diagnostic trouble codes.
  2. Start the engine from a cold condition.
  3. Monitor heater activation.
  4. Verify rapid oxygen sensor warm-up.
  5. Confirm oxygen sensor activity begins normally.
  6. Complete a full drive cycle.
  7. Verify oxygen sensor and catalyst readiness monitors complete.
  8. Confirm no pending or permanent DTCs return.
  9. 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

RepairTypical 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:

Many P0167 repairs involve correcting fuse, relay, wiring, or connector problems rather than replacing the oxygen sensor.

Manufacturer-Specific Notes

Ford

Inspect:

Heat-damaged wiring is a common cause of P0167 on Ford applications.

General Motors (Chevrolet/GMC)

Verify:

Shared heater power circuits commonly contribute to P0167.

Toyota/Lexus

Inspect:

Toyota factory scan tools provide enhanced heater circuit diagnostics.

Honda/Acura

Inspect:

Connector corrosion and damaged wiring commonly cause heater circuit faults.

Nissan/Infiniti

Verify:

High exhaust temperatures frequently damage downstream heater wiring.

BMW/Mercedes-Benz

Inspect:

Factory diagnostic software provides detailed heater circuit testing.

Hyundai/Kia

Inspect:

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:

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:

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