how to fix P0135 oxygen sensor issue on Ford Explorer Sixth Generation (2020-present)

Ford Explorer Sixth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0135

3 min read

565 words

Problem Statement

Learn how to diagnose and fix P0135 oxygen sensor issue in Ford Explorer (2020-present). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

P0135

Affected Component

Exhaust System

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the exhaust system to cool before handling components.

Symptoms

•Check engine light illuminated
•Poor fuel economy
•Rough idle
•Increased emissions
•Failed emissions test

Diagnostic Steps

1
Scan the vehicle's computer using an OBD-II scanner to confirm the P0135 code and check for any additional codes.
2
Inspect the wiring and connectors for the upstream oxygen sensor for any visible damage, corrosion, or loose connections.
3
Measure the voltage at the oxygen sensor heater circuit using a multimeter to verify proper voltage input.
4
Check the fuse related to the oxygen sensor heater circuit to ensure it is not blown.
5
Test the resistance of the oxygen sensor heater element to determine if it is within specifications.

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
•Oxygen sensor socket or wrench
•Wire brush
•Electrical contact cleaner

Parts Required

•Replacement upstream oxygen sensor

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Diagnostic Steps

1
Scan the vehicle's computer using an OBD-II scanner to confirm the P0135 code and check for any additional codes.
2
Inspect the wiring and connectors for the upstream oxygen sensor for any visible damage, corrosion, or loose connections.
3
Measure the voltage at the oxygen sensor heater circuit using a multimeter to verify proper voltage input.
4
Check the fuse related to the oxygen sensor heater circuit to ensure it is not blown.
5
Test the resistance of the oxygen sensor heater element to determine if it is within specifications.

Solution

1. Preparation

Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, wire brush, electrical contact cleaner, replacement oxygen sensor (if needed).
Safety Warnings: Disconnect the battery before working on electrical systems. Allow the exhaust system to cool before handling components.

2. Inspect and Repair Wiring

Inspect the wiring harness for the upstream oxygen sensor. Look for frayed wires, corrosion, or loose connections.
If any issues are found, repair the wiring as needed. Clean connectors with electrical contact cleaner.
Secure any loose wires and ensure proper insulation.

3. Replace Oxygen Sensor

Tools Required: Oxygen sensor socket or wrench.
Locate the upstream oxygen sensor on the exhaust manifold.
Disconnect the electrical connector from the oxygen sensor.
Use the oxygen sensor socket to unscrew the old sensor from the exhaust manifold. Note the orientation for the installation of the new sensor.
Apply anti-seize compound to the threads of the new oxygen sensor (if not pre-applied).
Install the new sensor by threading it into the manifold and tightening it to the manufacturer’s specified torque (typically around 30-40 lb-ft).
Reconnect the electrical connector to the new oxygen sensor.

4. Clear Codes and Test

Reconnect the battery if it was disconnected.
Use the OBD-II scanner to clear the P0135 code from the vehicle's computer.
Start the engine and allow it to reach operating temperature.
Perform a test drive to ensure the engine operates smoothly and check for the return of the check engine light.