how to fix Ford Explorer Fifth Generation (2011-2019) check engine light P0420 code

Ford Explorer Fifth Generation (2011-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0420

4 min read

606 words

Problem Statement

Learn how to diagnose and fix P0420 catalytic converter efficiency 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

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

Symptoms

•Check engine light illuminated
•Decreased fuel efficiency
•Engine misfire or rough idle
•Failed emissions test
•Unusual exhaust smell (rotten egg odor)
•Loss of acceleration power

Diagnostic Steps

1
Scan the vehicle's computer system using an OBD-II scanner to confirm the P0420 code and check for any additional codes.
2
Inspect the exhaust system for visible leaks or damage that may affect catalytic converter performance.
3
Check the oxygen sensors (upstream and downstream) for proper operation and any signs of wear or damage.
4
Measure the voltage output of the downstream oxygen sensor with a multimeter to ensure it is functioning normally.
5
Inspect the catalytic converter for any physical damage or blockage by tapping it lightly and listening for rattling sounds.
6
Verify the engine's air-fuel mixture by checking fuel trims with the scanner.

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
•Jack and jack stands
•Safety goggles
•Gloves

Parts Required

•Upstream oxygen sensor
•Downstream oxygen sensor
•Catalytic converter (if necessary)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan the vehicle's computer system using an OBD-II scanner to confirm the P0420 code and check for any additional codes.
2
Inspect the exhaust system for visible leaks or damage that may affect catalytic converter performance.
3
Check the oxygen sensors (upstream and downstream) for proper operation and any signs of wear or damage.
4
Measure the voltage output of the downstream oxygen sensor with a multimeter to ensure it is functioning normally.
5
Inspect the catalytic converter for any physical damage or blockage by tapping it lightly and listening for rattling sounds.
6
Verify the engine's air-fuel mixture by checking fuel trims with the scanner.

Solution

1. Preparation

Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, safety goggles, gloves.
Clear any stored codes in the vehicle's computer and take the vehicle for a test drive to confirm the P0420 code returns.

2. Inspect and Replace Oxygen Sensors

Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
Disconnect the battery: Disconnect the negative terminal to ensure safety while working with electrical components.
Remove the upstream oxygen sensor:
- Use a socket wrench to unscrew the sensor from the exhaust manifold.
- Disconnect the electrical connector.
Install the new upstream oxygen sensor:
- Apply anti-seize compound to the threads of the new sensor.
- Screw it into place and tighten to the manufacturer’s specifications (typically around 30 lb-ft).
- Reconnect the electrical connector.
Repeat for the downstream oxygen sensor: Follow the same steps to remove and replace the downstream sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

Check for blockage: If the catalytic converter is damaged or blocked, it needs to be replaced.
Raise the vehicle: Use a jack and jack stands to safely lift the vehicle.
Remove the catalytic converter:
- Disconnect the exhaust pipes at both ends of the catalytic converter using a socket set.
- Remove any mounting brackets or hangers.
Install the new catalytic converter:
- Position the new catalytic converter and connect it to the exhaust pipes.
- Secure all bolts and brackets to the manufacturer’s torque specifications.
Reconnect the battery: Reattach the negative terminal of the battery.