how to check for EVAP leaks on Ford F-150 13th Generation (2015-2020)

Ford F-150 13th Generation (2015-2020)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

4 min read

648 words

Problem Statement

Learn how to diagnose and fix EVAP leaks in Ford F-150 (2015-2020). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

Fuel System

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical components to avoid short circuits.
•Allow the engine to cool before performing inspections or repairs near hot components.

Symptoms

•Check engine light illuminated
•Fuel smell near the vehicle
•Poor fuel economy
•Difficulty in starting after refueling
•Increased emissions during testing
•Erratic idle or stalling

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific EVAP-related codes.
2
Visually inspect the EVAP system components, including hoses, connections, and the gas cap for cracks or damage.
3
Perform a smoke test to check for leaks in the EVAP system.
4
Check the integrity of the EVAP canister and its connections for signs of wear or damage.
5
Inspect the purge valve and vent valve operation by applying voltage directly to them to check for function.
6
Verify the fuel cap seal by performing a pressure test on the fuel system.

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
•Smoke machine
•Basic hand tools (socket set, screwdrivers)
•Multimeter

Parts Required

•Gas cap (if damaged)
•EVAP hoses (if damaged)
•Purge valve (if failed)
•Vent valve (if failed)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific EVAP-related codes.
2
Visually inspect the EVAP system components, including hoses, connections, and the gas cap for cracks or damage.
3
Perform a smoke test to check for leaks in the EVAP system.
4
Check the integrity of the EVAP canister and its connections for signs of wear or damage.
5
Inspect the purge valve and vent valve operation by applying voltage directly to them to check for function.
6
Verify the fuel cap seal by performing a pressure test on the fuel system.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a flat surface with the engine off and cool.
Disconnect the battery before starting work on electrical systems.

2. Inspect EVAP Components

Check the Gas Cap:
- Remove the gas cap and inspect the rubber seal for cracks or wear.
- Replace the gas cap if any damage is found.
Inspect Hoses and Connections:
- Visually examine all EVAP hoses and connections for signs of cracks or loose fittings.
- Replace any damaged hoses with OEM or equivalent parts.

3. Perform Smoke Test

Set Up Smoke Machine:
- Connect the smoke machine to the EVAP service port (usually located near the fuel tank).
- Ensure the vehicle is sealed (close the gas cap and any other access points).
Introduce Smoke:
- Activate the smoke machine and monitor for smoke escaping from any point in the EVAP system.
- Identify and mark any leak points.
Repair Leaks:
- For any leaks found, replace components as necessary (hoses, valves, canister).

4. Test Purge and Vent Valves

Access Purge Valve:
- Locate the purge valve (usually near the intake manifold).
- Disconnect the electrical connector.
Test Operation:
- Apply 12V directly to the purge valve terminals and listen for operation (should click).
- Replace if non-operational.
Vent Valve Testing:
- Locate the vent valve (often found near the fuel tank).
- Repeat the same voltage test as for the purge valve.

5. Reassemble and Clear Codes

Reconnect Components:
- Reattach all hoses, connectors, and the gas cap securely.
Reconnect Battery:
- Reconnect the vehicle's battery.
Clear Error Codes:
- Use the OBD-II scanner to clear any stored trouble codes.