P0135 Honda Civic - Diagnosis and Fixing the Problem

A vehicle's control module issues diagnostic Trouble Codes to indicate a malfunction in the car. Like every vehicle equipped with OBD2 diagnostic capabilities, the Honda Civic gives specific codes when its computer system senses a malfunction. One of these Diagnostic Trouble Codes is the P0135, which indicates an issue with the Civic's oxygen sensor.

P0134/P0135 code highlights

• Level of urgency:Medium
• Possible culprits:oxygen sensor1is malfunctioning, wiring problems
• Price for repair:$150 - $600
• If neglected:Fuel consumption growth, harsh work of the engine, failing emission test
• DIY repairs:Possible but complicated
• Can you drive?Yes

The Meaning of Code P0135 in Honda Civic

The P0135 is a common trouble code with Honda Civics. The code is defined as the oxygen sensor heater malfunctioning. The problem is known to have moderate to critical effects on your vehicle's engine. This means you can drive with this error code, but not for long. Continued driving with the P0135 code could lead to severe damage to your engine.

What Causes P0135 Code in Honda Civic

• Faulty Oxygen Sensor

The oxygen sensor is one of the possible reasons your Honda Civic "Service Engine Soon" light is illuminated. The sensor monitors and reports oxygen levels in the exhaust streams to the Engine Control Module. The control module uses the data provided to adjust the engine's ratio of gas to air to attain its ultimate efficiency.

The common signs of a faulty oxygen sensor include "Check Engine" light illuminating, loss of power, sluggish acceleration, irregular idling, and jerking when accelerating. A faulty oxygen sensor will also lead to excessive fuel consumption, higher exhaust emissions, and bad odor from the exhaust tailpipe.

• Damaged Wiring Harness

If the oxygen sensor or its wiring harness is damaged, it can lead to the "Check Engine" light illuminating and cause error code P0135 to show up. The wiring in the front and rear sensors is very susceptible to damage. The oxygen sensor is located under the chassis, where it's exposed to punishment from adverse road conditions such as water, mud, and also dust.

The wiring harness should be fixed and secured away from components such as the propeller shaft.

• Damaged Terminal(s)

The Honda Civic Control Module depends on several sensors to regulate the engine's performance and other components. The oxygen sensor enhances efficiency by monitoring the oxygen level in your vehicle's exhaust system.

To keep providing the correct information to the Engine Control Module, the oxygen sensor in your Honda Civic has to remain properly connected on each terminal. If the terminals are damaged, your computer system will sense a problem with the sensor and issue the code P0135, indicating a malfunction in the oxygen sensor heater.

When one of the terminals is damaged, the sensor is not properly connected. As a result, your vehicle will experience excessive fuel consumption and drivability issues, signs of a faulty oxygen sensor.

• Circuit Failures

The error code P0135 means there is a problem with the oxygen sensor. People usually rush to replace the sensor because it costs only a few dollars. However, the error code could be because your sensor system has a broken circuit or maybe because the circuit has blown a fuse.

As your Honda Civic grows older, some components will fail. If you have the error code P0135 and are convinced it is the oxygen sensor, you may start by checking the connection and testing it for a broken circuit.

• Wrong Oxygen Sensor

This is only possible if you recently installed a new oxygen sensor in your Honda Civic. If this is the case, the error code P0135 indicates that the new oxygen sensor is incompatible with your vehicle. Other explanations could be a wrong installation, or the new oxygen sensor was faulty even before the installation.

Diagnosing P0135 in Honda Civic

Before replacing any component, it is important to check and confirm what causes the Engine Control Module to issue the code P0135. You can use a multimeter to check if the voltage coming from the oxygen sensor is within its required parameters. This will help you determine whether your Civic's oxygen sensor is broken or has a loose wire connection. A faulty terminal can also cause the ECM to send in the P0135 code.

You can physically check the wiring if your toolbox doesn't have a multimeter. If the connection from the fuse box to either terminal has an issue, you can save yourself the cost of buying a new oxygen sensor by just fixing the wires.

There is also the option of using a voltage test light. This will help you determine whether the sensor is getting any voltage. A voltage test light is available online for only $5. If the test shows that the sensor is not getting any voltage, connect the light to the harness plug, shake the cables a little bit, and see what happens - if you notice any light, even as little as a flush, it confirms that your wiring is loose and causing the P0135 code to show up.

How Serious is Code P0135 in Honda Civic?

The code P0135 is not a severe issue. It won't cause your Civic to break down. However, the consequences are not pleasing. The first issue is that you will consume more fuel if this code isn't fixed. It will also cause drivability problems and high emissions. As such, resolving the issue as soon as possible is advisable.

How to Fix P0135 in Honda Civic

One of the common mistakes drivers make when diagnosing the trouble code P0135 is assuming that the oxygen sensor is faulty. This is a mistake because several issues could cause this code to come up. A loose wire connection, a leaking exhaust system, or even a malfunctioning computer system can cause the P0135 to appear.

It is advisable to run a deep diagnosis of the engine to confirm all your suspicions. Don't replace any components unless you are sure. Sometimes you can replace all the parts your diagnosis suggested and still have this code appearing. It is advisable to have a professional mechanic run the diagnosis and fix the problem.

Step-By-Step Guide to Fix the Code P0135 in Honda Civic

• Start by checking all the oxygen sensor wires around the engine. Ensure they are all secure and in good condition.
• If you notice any loose wires or faulty connectors, ensure you replace them and clean anything covered with dirt.
• Now, using the OBDII scanner, clear the error code P0135, and take your Civic for a short drive.

If you have given the car enough time to build up the required operating temperature, but the code still shows up, check the following:

• Ensure the exhaust system does not have any leaks due to cracks. Check the system's undersides for weak spots.
• Check the engine ground for any corrosion. If you notice any, you should install a new ground.
• Using a vacuum gauge, test the catalytic converter to ensure the engine operates at its desired temperature, around 18 Hg. Rev the engine and confirms if it returns to that range. It would help if you also cleaned the catalytic converter.
• Check for blown fuses in the oxygen sensor circuit, especially on the heater. It is not surprising that all your troubles are due to a faulty fuse.

You can settle for a new sensor if you have done all these and the code is still there. If it still appears even with the new sensor, you may require the help of a professional mechanic. There could be an underlying problem in your engine or other systems.

The Code P0135 Keeps Recurring; How to Prevent this?

Damaged wires, blown fuses, and short circuits are the common causes of the error code P0135. What can you do to keep these components from damage?

Check your engine regularly to ensure there aren't any loose wire connections. Keep the wires from coming into contact with components that can damage them. Also, ensure they do not overlap. This can strain them and cause the wires to short-circuit.

Keep your engine's internal components free from corrosion by spraying them regularly with anti-rust spray. Corrosion is bad for terminals.

Conclusion

Monitoring the oxygen level in your Honda Civic's exhaust streams is one way of ensuring that the engine is at its optimal performance. It is only the oxygen sensor that can do this monitoring. If it fails, you can experience several problems, including drivability problems, high emissions, and excessive fuel consumption.

When there's a problem with the oxygen sensor, your Engine Control Module issues the error code P0135. Most of the time, this code appears due to a faulty sensor. However, there are other possible causes for the code to show up.

Good luck finding the fault. If you encounter obstacles you can't bypass, you should visit your professional mechanic and let them handle the problem.