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

high

Severity

Error Code: P0420

4 min read

637 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix P0420 exhaust system issue 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 to prevent electrical shock.

Symptoms

•Check engine light illuminated
•Decreased fuel efficiency
•Poor acceleration or loss of power
•Increased exhaust emissions
•Rattling noise from the catalytic converter area

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm the presence of the P0420 code.
2
Inspect the exhaust system for any visible leaks, particularly before and after the catalytic converter.
3
Check the operation of the upstream and downstream oxygen sensors using a multimeter or scan tool.
4
Perform a visual inspection of the catalytic converter for physical damage or signs of overheating.
5
Measure the temperature difference between the inlet and outlet of the catalytic converter; a significant drop indicates inefficiency.
6
Check for any additional codes related to the fuel system or engine misfires that could affect the catalytic converter's performance.

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
•Wrench set
•Oxygen sensor socket
•Torque wrench
•Exhaust pipe cutter

Parts Required

•New oxygen sensors (if faulty)
•New catalytic converter (if necessary)
•Exhaust gaskets or clamps (if needed)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm the presence of the P0420 code.
2
Inspect the exhaust system for any visible leaks, particularly before and after the catalytic converter.
3
Check the operation of the upstream and downstream oxygen sensors using a multimeter or scan tool.
4
Perform a visual inspection of the catalytic converter for physical damage or signs of overheating.
5
Measure the temperature difference between the inlet and outlet of the catalytic converter; a significant drop indicates inefficiency.
6
Check for any additional codes related to the fuel system or engine misfires that could affect the catalytic converter's performance.

Solution

1. Preparation

Gather required tools and parts.
Ensure the vehicle is parked on a level surface and securely raise it using jack stands.
Disconnect the battery to prevent electrical shock.

2. Inspect and Repair Exhaust System

Tools Required: Socket set, wrench set, exhaust pipe cutter (if needed)
- Inspect all exhaust joints and connections for leaks. Tighten any loose clamps or bolts.
- If leaks are found, replace gaskets or clamps as required. Use high-temperature exhaust sealant if necessary.

3. Test Oxygen Sensors

Tools Required: OBD-II scanner, multimeter
- Connect the OBD-II scanner to the vehicle and monitor the live data for the upstream and downstream oxygen sensors.
- If either sensor is not functioning within normal parameters, replace the faulty sensor. Follow these sub-steps:
  - Disconnect the electrical connector from the faulty sensor.
  - Use the appropriate wrench to unscrew the sensor from its mounting location.
  - Install the new sensor and reconnect the electrical connector. Ensure it is secure.

4. Replace Catalytic Converter (if necessary)

Tools Required: Socket set, oxygen sensor socket, ratchet, torque wrench
- If diagnostic tests indicate a faulty catalytic converter, proceed to replace it:
  - Remove the oxygen sensors from the catalytic converter using the oxygen sensor socket.
  - Unscrew the catalytic converter from the exhaust system (typically held by bolts or flanges).
  - Install the new catalytic converter by reversing the removal steps. Ensure all bolts are torqued to the manufacturer's specifications.
  - Reinstall the oxygen sensors into the new catalytic converter.

5. Reset the Engine Control Module

Tools Required: OBD-II scanner
- Reconnect the battery and use the OBD-II scanner to clear the P0420 code from the ECM memory.