Is your Nissan’s check engine light on? Is it showing the P1456 error code after the diagnosis? Well, the P1456 error code on your Nissan indicates that the Evaporative Emission Control System (EVAP) has a very small leak. Since the P1456 code can result from various causes, it’s best to check out each one to clear it.
This article will address the P1456 Nissan trouble code. In addition, I’ll tell you what it means, the common symptoms, causes, and how to fix it.
Table of Contents
What Does P1456 Mean On Your Nissan Car?
The P1456 code definition is an evaporative emission control system leak. It indicates a fuel vapor leak problem or the EVAP control system has an issue with the purge flow.
Understanding The Nissan’s EVAP System
The EVAP system prevents fuel vapors from leaking into the atmosphere. The engine control unit (ECU) regulates the canister vent valve and allows the fumes to flow into the charcoal canister. These fumes are absorbed by charcoal pellets and stored in the charcoal canister. Once the engine is running and required conditions are met, fuel vapors will be purged into the engine through lines and purge valve to burn off.
Normally the vent valve is open. Only when the ECU performs leak tests on the EVAP does it close. If the tests show that the Evaporative system is not maintaining pressure, it identifies an EVAP leak with the P1456 code.
Is It Safe to Drive When P1456 Is Detected On Your Nissan Car?
The severity of the issue is low, and you can continue driving the vehicle for a short while. Nonetheless, it is recommended not to drive your car more than 30-50 miles with an EVAP leak and you shouldn’t wait for longer than a month to get this code fixed. This is because it can lead to drivability problems, excessive fuel consumption, and cause car pollution as well.
Common Symptoms of P1456 Nissan Code
When your Nissan has the P1456 code, it’s going to have a few symptoms, including:
- Check Engine Light (CEL) comes on.
- You smell burning fuel in the cabin.
- Your car loses drivability and fewer miles to the gallon.
Causes of P1456 Nissan Code
Problems with the EVAP system are a result of many causes. These are the most common ones.
Gas Cap Issues
The fuel cap keeps fuel vapors in the tank and prevents them from escaping into the atmosphere. When it is missing or loose, the car’s computer system will detect an EVAP leak, leading to the P1456 error code.
Additionally, using the wrong fuel cap for your particular Nissan can cause a P1456 code since it does not seal completely, increasing emissions.
Clogged Or Damaged Charcoal Canister
The charcoal canister maintains the pressure of the EVAP system. Suppose the car’s computer detects that the charcoal canister is not at the correct pressure or doesn’t have the proper airflow. In that case, it will trigger the check engine light.
Faulty Fuel Tank Pressure Sensor
Over time, exposure to corrosive fuel vapors leads to failure of the fuel tank pressure sensor. Therefore, it couldn’t read the pressure in the fuel system to detect exact evaporative leaks.
Faulty Canister Vent Valve Or Canister Purge Valve
The vehicle’s computer controls the canister vent valve. When the computer detects that it is purging fumes at a lower or higher rate than expected, it will trigger the P1456 error code.
The same error code will come on if the canister purge valve fails. It prevents the engine intake vacuum from taking the exact amount of fuel vapors from the EVA canister into the engine intake manifold.
Leaks In The Fuel Vapor Lines
The EVAP system includes fuel vapor lines that can develop leaks in the hoses, filler neck tubing, or the tubing connecting the carbon canister to the fuel tank. Leaks prevent the EVAP system from containing the fuel vapors. Hence, the ECU will detect these and throw the P1456 code.
How to Fix the P1456 Nissan Code
The P1456 Nissan Code has easy and complex fixes. We’ll look at each of them since some you can remedy at home while others you may need help from an auto technician.
When the check engine light comes up, diagnose the vehicle using an OBD2 scanner first. You’ll then verify that you have a P1456 code and no other codes are present. A good OBD2 scanner will come in handy since it can read manufacturer-specific codes, in this case, the P1456 error code. After which, you can perform the necessary repairs to clear the P1456 Nissan error code. Here are the possible fixes.
Tighten/ Replace Gas Cap
You Will Need:
- WD-40 cleaner
- Exact model gas cap
How To:
Step 1: Locate the gas cap on the vehicle’s exterior and inspect its condition.
Step 2: Spray it with the WD-40 cleaner, then wipe it clean.
Step 3: Examine the gas cap for deterioration or physical damage.
- If it’s in good condition, tighten it.
- If not, replace it with the correct model gas cap
Step 4: Check the OBDII scanner
Clean/ Replace Charcoal Canister
A clogged or damaged charcoal canister cannot collect fuel vapors. Before replacing the charcoal canister, you can clean it with an air compressor to determine if it’s faulty or if some of its lines are blocked.
You Will Need:
- Air compressor
- Flathead screwdriver
- New canister if old one is damaged
How To:
Step 1: Locate the fuel vapor canister on the driver’s side of your Nissan, close to the rear tire
Step 2: Use a flathead screwdriver to remove the top and bottom lines from the canister. The canister has one line on the bottom and three lines on the bottom.
Step 3: Start the air compressor, let it reach a pressure of 50 psi, and then shut it off
Step 4: Insert the air compressor’s nozzle into the canister’s outer vent control valve pipe. It’s the bigger separate pipe on one end of the canister.
Step 5: Close the ends of the other two pipes with your fingers and then release the air from the nozzle. Let the air blow into the canister for about two minutes. Remove the two fingers from the openings and place one finger near the outlet at the bottom.
Step 6: Apply the air again and determine whether air is flowing to the bottom of the pipe. This ensures that it’s clean and there are no blockages.
Step 7: Check the OBDII scanner
In case the code hasn’t been cleared, all you need is a new canister and reconnect it in reverse.
Replace Fuel Tank Pressure Sensor
The fuel tank pressure sensor (FTP) is another likely faulty EVAP component.
You Will Need:
- A new FTP
- 10mm socket
- Needle-nose pliers
- WD-40 cleaner
- Dielectric grease
How To:
Step 1: Locate the fuel tank pressure sensor at the right rear of the fuel tank. It has a bracket bolted to the frame not far from the fuel line. A 10mm bolt secures it to the chassis, so you will use the 10mm socket to release it.
Step 2: Grab a pair of needle-nose pliers to hold the clamp from the back. Release the sensor by pushing on the tab. Also, avoid holding the harness and pulling on the sensor simultaneously, as this could fray a wire in the plug. If the tab is stuck, saturate it with WD-40 cleaner and wait for at least 30 minutes. The sensor will be easier to remove by then.
Step 3: Apply dielectric grease inside the harness socket and the new sensor to prevent water damage to the pin.
Step 4: Insert the new sensor and finish by tightening the 10mm bolt on the chassis.
Step 5: Check the OBDII scanner
Diagnose Leaks In The Fuel Lines
It’s nearly impossible to detect leaks in the EVAP system without special equipment. You will need a smoke machine to test for leaks. Nowadays, you can find smoke machines for around $100. Still, you can find damaged hoses by visually inspecting the EVAP system.
You Will Need:
- Smoke machine
- Schrader valve removal tool
How To:
Step 1: Locate the EVAP service port in the engine compartment. It has a green cap.
Step 2: Remove the Schrader valve using a Schrader valve tool. It has left-hand threads, so you will turn it clockwise.
Step 3: Insert the service port adapter and the smoke nozzle into the short hose leading from the service port adapter.
Step 4: Close the solenoid valve using the scan tool before pressurizing the system since it’s usually open. You can also plug the lines near the vents.
Step 5: Connect the smoke machine to the vehicle’s battery and an air compressor, then open the flow control valve. Check to see that the pressure is rising on the pressure gauge. Next, close the flow control valve and observe if the pressure decreases to indicate a leak in the system.
Step 6: Turn on the smoke machine and remove the fuel cap at the same time. Wait for the smoke to start exiting the fuel neck.
Step 7: Replace the fuel cap and observe as smoke exits from the leak source.
Once you’ve located the leak source, apply the necessary repairs and recheck the system for any more leaks. At this point, you’ll be able to clear the P1456 code using an OBD2 scanner.
Note
Unlike possible fixes mentioned above, diagnosing and replacing the canister vent valve or canister purge valve is quite complicated. The process requires performing electrical testing and using the right tools at home. Besides, you’ll need to identify symptoms such as pressure in the fuel tank, rough idle, or poor engine performance other than the P1456 code before going for the replacement.
So, if you see these symptoms alongside the check engine light, it’s best to ask for a mechanic’s help.
Conclusion
In summary, the P1456 code Nissan indicates an emission control system leak. By now, you can undertake the necessary fixes to clear the code with ease. As you can see, it’s not a complicated process if you have the right tools.
Good Luck!
