P0456 Pontiac Code - EVAP Control System Leak Detected Very Small Leak
Quick Answer
The Powertrain Control Module (PCM) tests the Evaporative Emission (EVAP) system for the following conditions: - Large and small leaks - Excess vacuum - Purge flow during non-commanded conditions - Fuel Level and Fuel Pressure sensor faults - EVAP Purge and Vent Valve faults The PCM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
- What it means
- P0456 Pontiac indicates EVAP Control System Leak Detected Very Small Leak.
- Common causes
- Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close.
- Severity
- Low - monitor the vehicle and repair when practical.
- Can I drive?
- The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
Code P0456 Pontiac Description
- Large and small leaks
- Excess vacuum
- Purge flow during non-commanded conditions
- Fuel Level and Fuel Pressure sensor faults
- EVAP Purge and Vent Valve faults
The PCM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. The PCM commands both the EVAP Purge Solenoid and the EVAP Vent Valve ON when the conditions are met in order to apply an engine vacuum to the EVAP system. The PCM commands the EVAP Purge Solenoid OFF once the system has reached a predetermined level of vacuum. This test verifies if a vacuum can be achieved in the EVAP system. Failure to develop a vacuum may be caused by a large leak or a restriction.
What are the Possible Causes of the DTC P0456 Pontiac?
- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking
How to Fix the DTC P0456 Pontiac?
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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0456 Pontiac code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P0456 Pontiac code?
Need more information on how to fix the P0456 Pontiac code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0456 Pontiac code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0456 Pontiac Code
1. What does OBDII code P0456 mean on a Pontiac?
P0456 indicates a "Very Small Leak Detected" in the EVAP (Evaporative Emission Control) system, which prevents fuel vapors from escaping into the atmosphere.
2. What are the common symptoms of a P0456 code on a Pontiac?
The most common symptom is the Check Engine Light turning on. There are usually no noticeable performance issues, but a faint fuel smell might be present.
3. What causes a P0456 code to appear on a Pontiac?
Common causes include a loose or faulty gas cap, damaged EVAP hoses, a malfunctioning purge or vent valve, or a small leak in the EVAP canister.
4. How do I fix a P0456 error code on my Pontiac?
Start by tightening or replacing the gas cap. If the code persists, inspect the EVAP system hoses and valves for damage or leaks, and replace faulty components.
5. Can a loose gas cap trigger the P0456 code on a Pontiac?
Yes, a loose, damaged, or improperly sealed gas cap is one of the most common reasons for this code.
6. Is it safe to drive with a P0456 code on my Pontiac?
Yes, it is generally safe to drive, but you should address the issue promptly to ensure your EVAP system is functioning properly and to avoid potential emissions test failures.
7. How can I diagnose the P0456 code on my Pontiac?
Use an OBDII scanner to confirm the code, then visually inspect the gas cap, EVAP hoses, canister, and valves for signs of wear or damage.
8. Will clearing the P0456 code fix the problem permanently?
Clearing the code will turn off the Check Engine Light temporarily, but the issue will likely return unless the underlying cause is resolved.
9. What tools are needed to repair a P0456 code on a Pontiac?
You may need an OBDII scanner, a gas cap replacement, a smoke machine to locate leaks, and basic hand tools for removing and replacing EVAP components.
10. Can extreme weather conditions cause a P0456 code on a Pontiac?
Yes, extreme heat or cold can cause seals and hoses in the EVAP system to shrink or crack, potentially triggering this code.
Discuss the causes and fixes for P0456 Pontiac OBDII Code
Code P0456 Pontiac comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
