P1456 1999 Honda Civic Code - Evaporative Emissions Control System Leakage Fuel Tank
Quick Answer
The evaporative emission (EVAP) control system stores fuel vapor from the fuel tank in the EVAP canister temporarily to prevent it from escaping to the atmosphere and to enable it to be drawn into the engine by intake manifold vacuum and burned. Common causes include Missing Fuel Filler Cap, Incorrect Fuel Filler Cap used, Fuel Filler Cap remains open or fails to close. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1456 1999 Honda Civic indicates Evaporative Emissions Control System Leakage Fuel Tank.
- Common causes
- Common causes include Missing Fuel Filler Cap, Incorrect Fuel Filler Cap used, Fuel Filler Cap remains open or fails to close.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P1456 1999 Honda Civic Description
The EVAP control system leak detection method improves the accuracy and frequency of the detection by determining faulty components and vapor leakage for each part. The EVAP control system (from the purge valve to the fuel tank) is divided into two parts. One is the "EVAP Canister Side" (from the EVAP two-way valve to the purge valve) and the other is the "Tank Side" (from the EVAP two-way valve to the fuel tank). There is 0.04-inch leak detection and 0.02-inch leak detection. If the 0.04 inch leak detection results are OK, the 0.02-inch leak detection runs. The P1456 code is detected when the EVAP system has a very small leak.
What are the Possible Causes of the DTC P1456 1999 Honda Civic?
- Missing Fuel Filler Cap
- Incorrect Fuel Filler Cap used
- Fuel Filler Cap remains open or fails to close
- Foreign matter caught in the Fuel Filler Cap
- Faulty EVAP Two-Way Valve
- Faulty EVAP Bypass Solenoid Valve
- Faulty EVAP Canister
How to Fix the DTC P1456 1999 Honda Civic?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1456 1999 Honda Civic code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80β$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P1456 1999 Honda Civic Code
1. What does OBDII code P1456 on a 1999 Honda Civic mean?
Code P1456 indicates a small leak in the evaporative emissions control system related to the fuel tank.
2. What are the common symptoms of OBDII code P1456 on a 1999 Honda Civic?
Common symptoms include the check engine light illuminating on the dashboard and potential fuel odor near the vehicle.
3. What are the possible causes of OBDII code P1456 on a 1999 Honda Civic?
Causes can include a loose or damaged gas cap, a leaking fuel tank, a faulty purge control valve, or a cracked or damaged EVAP system hose.
4. How can I diagnose the cause of OBDII code P1456 on my 1999 Honda Civic?
You can start by checking the gas cap for proper sealing, inspecting the fuel tank and EVAP system components for leaks, and using a diagnostic tool to check the purge control valve functionality.
5. Can OBDII code P1456 on a 1999 Honda Civic be fixed at home?
Depending on the cause, some DIY fixes include tightening or replacing the gas cap, repairing or replacing damaged hoses, or cleaning or replacing the purge control valve.
6. Is it safe to continue driving with OBDII code P1456 on a 1999 Honda Civic?
While the vehicle may still operate normally, it's recommended to address the issue promptly to prevent potential fuel leaks and ensure proper emissions control.
7. How much does it typically cost to repair OBDII code P1456 on a 1999 Honda Civic?
Repair costs can vary depending on the exact cause, but they may range from around $100 for simple fixes like a gas cap replacement to several hundred dollars for more complex repairs involving component replacement.
8. Can a mechanic reset the OBDII code P1456 on my 1999 Honda Civic after fixing the issue?
Yes, once the underlying problem is repaired, a mechanic can use a diagnostic tool to clear the error code and reset the check engine light.
9. How often does OBDII code P1456 reoccur on a 1999 Honda Civic after being fixed?
If the issue is properly diagnosed and repaired, the code should not reoccur unless a new problem develops in the evaporative emissions control system.
10. Are there any preventive maintenance tips to avoid OBDII code P1456 on a 1999 Honda Civic?
Regularly checking the gas cap for tightness, inspecting the EVAP system components for damage, and following the manufacturer's recommended maintenance schedule can help prevent this code from appearing.
Discuss the causes and fixes for P1456 1999 Honda Civic OBDII Code
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The sensor is attached to the EVAP canister. The canister ins underneath your Accord near the gas tank.
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I ran out of gas and was refueling with a gas can, a piece of the gas can fell inside my tank, would that cause for this code to appear?
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It's possible that the piece of the can it's blocking or have damage one of the sensors.
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Did you hear the piece drop inside the tank? It may be stuck in the tank filler tube. Try inserting a road or something to check if is in the filler tube. If is there then you can just remove the filler tube.
If is not there, then you may no need to drop the gas tank, you could try removing the fuel pump and try reaching for the piece of the can. The fuel pump access panel is under the rear seat.

Click here to enlarge image.
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I didn't hear anything drop, but I seen it go in. I've been driving it to and from work as well with filling it up with gas, wouldn't the flow of gas push it down?
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