The P1167 trouble code for Honda Accord vehicles indicates a problem with the air/fuel ratio sensor heater circuit. Replacing the sensor is the most common fix.
As an experienced Honda technician and expert on Honda engine codes, I want to share my knowledge and help Honda Accord owners understand and resolve this frustrating check engine light issue. By the end of this detailed guide, you’ll have a complete understanding of the P1167 code – what causes it, how to diagnose it, and how to finally fix it for good.
What Does The P1167 Code Mean On A Honda Accord?
The P1167 error code stands for “Air/Fuel Ratio Sensor 1 Heater Circuit Malfunction”. It indicates that there is a problem with the heated oxygen sensor’s heater circuit, which is causing it to operate incorrectly.
The heated oxygen sensor (also known as the air/fuel ratio sensor) is located in the exhaust system and measures the oxygen content of the exhaust gases. It generates a voltage signal that tells the engine computer whether the engine is running rich (too much fuel, not enough air) or lean (too much air, not enough fuel).
When the engine starts, a heater circuit is used to warm up the oxygen sensor so it can quickly reach operating temperature. The P1167 error code indicates that this heater circuit is malfunctioning in some way.
What Causes The P1167 Code On A Honda Accord?
The P1167 code indicates that there is some kind of malfunction with the heated oxygen sensor’s heater circuit. But what specifically causes this heater circuit to stop working properly?
Here are the most common culprits behind the dreaded P1167 code on Honda Accord models:
- Failed Oxygen Sensor
- Faulty Heater Circuit Wiring
- Blown Fuse
- ECM Failure
Failed Oxygen Sensor
The oxygen sensor itself failing or reaching the end of its lifespan is one of the most common causes of the P1167 code. Oxygen sensors deteriorate over time as a result of constant exposure to high exhaust temperatures. The typical service life is between 60,000 and 100,000 miles. When the O2 sensor becomes old and worn out, it can set off the P1167 heater circuit code.
Signs of a failing oxygen sensor:
- Reduced engine performance
- Poor fuel economy
- Failed emissions test
- Check engine light comes on
How to test: Swap the suspect O2 sensor with one from another cylinder bank. If the code follows the sensor, it needs to be replaced.
Faulty Heater Circuit Wiring
The wiring from the engine computer to the oxygen sensor is also susceptible to failure. Corrosion, loose connections, shorts, and open circuits can all disrupt the heater circuit and set P1167.
Some wiring failures that trigger P1167:
- Chafed wires shorting to ground
- Corroded or burnt terminals
- Broken wires create an open circuit
- Pinched wire harness
- Melted socket terminals
How to test: Carefully inspect the wiring for damage. Check resistance on heater circuit wires. Monitor the voltmeter for power fluctuations.
A blown fuse for the oxygen sensor heater circuit is one simple cause of the P1167 code. This can occur as a result of normal electrical overloads or faulty wiring drawing an excessive amount of current through the circuit.
How to Perform the Test: Using your Accord’s fuse diagram, locate the correct fuse. Pull the fuse and look inside for a broken wire or discoloration on the metal caps. If the fuse is faulty, replace it with an identical new one.
P1167 can occur in rare cases when the engine computer, which controls the voltage to the oxygen sensor heater circuit, fails. However, this would most likely set other codes as well, causing drivability issues.
How to Perform the Test: A faulty ECM cannot be easily tested using standard tools. Before replacing the ECM, it is best to exhaust all other diagnostic options.
Diagnosing The P1167 Honda Accord Code
Diagnosing the P1167 code involves systematically testing different components to isolate the cause of the problem:
- Scan for Codes
- Inspect Fuses
- Check wiring
- Check Sensor Operation
- Swap Sensors
Scan for Codes
Scan the vehicle for trouble codes using an OBD2 scanner. Take note of any other codes that may be present along with P1167.
Locate the fuse box and check the fuse that supplies power to the oxygen sensor heater circuit. Replace if blown.
Visually inspect the wiring harness leading to the oxygen sensor. Look for damage, loose connections, etc. Perform continuity or resistance tests on wires.
Check Sensor Operation
Monitor the oxygen sensor activity with a scan tool. It should quickly switch between rich and lean readings. Measure heater circuit resistance, which should be between 10-40 ohms.
If the oxygen sensor checks out OK, swap it with the other oxygen sensor in the exhaust bank to test. Clear codes and recheck.
Replacing The O2 Sensor To Fix P1167
In most cases, replacing the malfunctioning oxygen sensor will be required to repair the P1167 code and heater circuit on your Honda Accord. Here are the step-by-step instructions for DIY oxygen sensor replacement:
- Locating the Faulty O2 Sensor
- Removing the Old Oxygen Sensor
- Installing the New O2 Sensor
- Reconnecting Electrical Circuit
- Completing Repair and Verification
Locating the Faulty O2 Sensor
- The oxygen sensor will be located in the exhaust system, either before or after the catalytic converter. Consult a repair manual to find the exact location.
- O2 sensors have a wire harness plugged into them – trace the wires back to identify the sensor.
- Upstream sensors are located closer to the engine; downstream sensors are further back.
Removing the Old Oxygen Sensor
- Allow the engine and exhaust to fully cool before attempting removal.
- Disconnect the wire harness from the oxygen sensor.
- Use penetrating oil to loosen the sensor if corroded or stuck.
- Use the correct oxygen sensor socket to unthread the sensor from the exhaust.
Installing the New O2 Sensor
- Do not remove the protective cap from the new sensor until it is ready to install.
- Apply anti-seize compound to sensor threads.
- Thread in the new O2 sensor by hand until snug.
- Tighten the sensor to proper torque (usually 30-45 ft-lbs) with the socket. Do not over tighten.
Reconnecting Electrical Circuit
- Plug the wire harness back into the new oxygen sensor. Listen for a click.
- Secure the connector with any clips or fasteners. Clear any loose wires.
- Restore any components removed for access during installation.
Completing Repair and Verification
- Clear any codes with an OBD2 scanner. Road test vehicle.
- Monitor oxygen sensor activity with a scanner to verify proper operation.
- Check for leaks at the sensor location. Retighten if any exhaust leaks are found.
Frequently Asked Questions
Is It Safe To Drive With The P1167 Code?
The car is safe to drive for short trips if necessary, but the issue should be diagnosed and repaired promptly. Driving long distances or heavily loading the engine is not recommended.
How Much Does It Cost To Fix P1167?
Repair costs typically range from $125-$350. The oxygen sensor replacement is around $125-200. Additional wiring repairs or an ECM replacement can cost over $350.
Can A Bad Oxygen Sensor Cause Other Issues?
Yes, a malfunctioning oxygen sensor can lead to reduced engine performance, increased emissions, poor fuel economy, and even engine damage if left unattended.
Are There Any Quick Fixes For P1167?
Unfortunately, no. Since this code deals with a circuit malfunction, it requires proper diagnostic testing and repair. Simple fixes like clearing the code will only provide temporary relief.
How Do I Reset The P1167 Code?
Use an OBD2 scanner to clear the check engine light and reset P1167 after completing the repair. The code will return if the underlying problem is not addressed.
Honda Accord owners can troubleshoot P1167 with a basic understanding of the oxygen sensor heater circuit and a systematic diagnostic approach. Replacing the faulty heated oxygen sensor, inspecting wiring, and testing fuses will frequently resolve this issue and permanently turn off the check engine light. As a certified technician, I hope I’ve given you the knowledge and confidence to tackle P1167 on your Honda.
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