how to fix the P0138 code on my Honda Accord 9th Generation (2013-2017)

Honda Accord Eleventh Generation (2023-present)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0138

3 min read

500 words

Problem Statement

Learn how to diagnose and fix P0138 oxygen sensor issue in Honda Accord 2013-2017. Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

P0138

Affected Component

Exhaust System

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the engine to cool before touching exhaust components.

Symptoms

•Check engine light illuminated
•Poor fuel economy
•Rough idle
•Increased emissions
•Engine stalling during idle

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0138 and check for any related codes.
2
Inspect the wiring and connectors of the downstream oxygen sensor for damage or corrosion.
3
Measure the voltage output of the downstream oxygen sensor using a multimeter.
4
Check for exhaust leaks before the oxygen sensor which could affect sensor readings.
5
Inspect the fuel system for issues such as clogged fuel injectors or a failing fuel pump.
6
Test the ECM for proper functionality in processing signals from the oxygen sensor.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Multimeter
•Socket set
•Torque wrench
•Safety gloves

Parts Required

•New downstream oxygen sensor

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0138 and check for any related codes.
2
Inspect the wiring and connectors of the downstream oxygen sensor for damage or corrosion.
3
Measure the voltage output of the downstream oxygen sensor using a multimeter.
4
Check for exhaust leaks before the oxygen sensor which could affect sensor readings.
5
Inspect the fuel system for issues such as clogged fuel injectors or a failing fuel pump.
6
Test the ECM for proper functionality in processing signals from the oxygen sensor.

Solution

1. Preparation

Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, and safety gloves.
Disconnect the battery to prevent electrical shorts.

2. Inspect and Repair Wiring

Sub-step 1: Remove the underbody cover to access the oxygen sensor wiring.
Sub-step 2: Visually inspect the wiring harness for fraying, corrosion, or damage.
Sub-step 3: Use a multimeter to check continuity in the wires. Repair or replace any damaged wiring.

3. Replace Downstream Oxygen Sensor

Sub-step 1: Locate the downstream oxygen sensor (usually located before the catalytic converter).
Sub-step 2: Disconnect the electrical connector from the oxygen sensor.
Sub-step 3: Use a socket wrench to remove the old oxygen sensor from the exhaust pipe.
Sub-step 4: Apply anti-seize compound to the threads of the new oxygen sensor.
Sub-step 5: Install the new oxygen sensor and torque it to the manufacturer’s specifications (usually around 30 lb-ft).
Sub-step 6: Reconnect the electrical connector to the new oxygen sensor.

4. Reset the ECM

Sub-step 1: Reconnect the battery.
Sub-step 2: Use the OBD-II scanner to clear the stored error codes from the ECM.