how to fix P0420 code on Ford Explorer Fifth Generation (2011-2019)

Ford Explorer Fifth Generation (2011-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0420

3 min read

579 words

Problem Statement

Learn how to diagnose and fix P0420 catalytic converter efficiency issues in Ford Explorer (2011-2019). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

P0420

Affected Component

Exhaust System

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

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

Symptoms

•Check engine light illuminated
•Decreased fuel economy
•Poor acceleration
•Sulfur smell from exhaust
•Engine stalling or misfiring
•Failed emissions test

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0420 and check for any additional codes.
2
Inspect the exhaust system for visible leaks or damage that could affect catalytic converter performance.
3
Check the oxygen sensors (pre-cat and post-cat) for proper operation and signal.
4
Measure the temperature difference between the inlet and outlet of the catalytic converter using an infrared thermometer.
5
Verify the condition of the engine’s air-fuel mixture and check for any vacuum leaks.
6
Inspect the catalytic converter for physical damage or clogging.

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
•Socket set
•Torque wrench
•Infrared thermometer
•Wrench set

Parts Required

•Oxygen sensors (if needed)
•Catalytic converter (if needed)
•Exhaust gaskets (if needed)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0420 and check for any additional codes.
2
Inspect the exhaust system for visible leaks or damage that could affect catalytic converter performance.
3
Check the oxygen sensors (pre-cat and post-cat) for proper operation and signal.
4
Measure the temperature difference between the inlet and outlet of the catalytic converter using an infrared thermometer.
5
Verify the condition of the engine’s air-fuel mixture and check for any vacuum leaks.
6
Inspect the catalytic converter for physical damage or clogging.

Solution

1. Preparation

Gather tools and parts required for the repair.
Ensure the vehicle is parked on a level surface and the engine is cool.
Disconnect the negative battery terminal.

2. Inspect and Replace Oxygen Sensors

2.1 Locate the pre-cat (upstream) and post-cat (downstream) oxygen sensors on the exhaust system.
2.2 Using a socket wrench, carefully remove both oxygen sensors.
2.3 Inspect the sensors for any signs of damage or contamination.
2.4 If faulty, install new oxygen sensors, ensuring they are properly tightened (generally to the manufacturer's specification, often around 30-40 ft-lbs).
2.5 Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

3.1 If the catalytic converter is determined to be faulty after testing, disconnect the exhaust pipes leading to and from the catalytic converter.
3.2 Remove any mounting bolts using a socket set, taking care to preserve any gaskets for reuse if they are in good condition.
3.3 Remove the old catalytic converter and install the new one, ensuring it fits securely and aligns correctly with the exhaust system.
3.4 Torque bolts to the manufacturer's specifications, typically around 30-40 ft-lbs.
3.5 Reinstall any gaskets or seals as needed and reconnect the exhaust pipes.

4. Reconnect Battery and Clear Codes

4.1 Reconnect the negative battery terminal.
4.2 Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
4.3 Start the engine and allow it to reach operating temperature.