Diagnostic Trouble Code
P0456
Evaporative Emissions System - Small leak detected
Technical Description P0456
Evaporative Emissions System - Small leak detected
What Does This Mean P0456?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model.
The Powertrain Control Module (PCM) at different times performs various tests on the EVAP system. OBD II Enhanced EVAP systems are in place to keep fuel tank vapors from venting into the atmosphere, and instead purges them into the engine to be burned.
Regular pressure tests are conducted by the PCM to monitor the sealed system for leaks. The PCM monitors the EVAP system pressure by watching the fuel tank pressure (FTP) sensor. When the sensor indicates a small leak in the EVAP system, this code is set.
Related evaporative emission trouble codes include P0450, P0451, P0452, P0453, P0454, P0455, P0457, P0458, and P0459.
The Powertrain Control Module (PCM) at different times performs various tests on the EVAP system. OBD II Enhanced EVAP systems are in place to keep fuel tank vapors from venting into the atmosphere, and instead purges them into the engine to be burned.
Regular pressure tests are conducted by the PCM to monitor the sealed system for leaks. The PCM monitors the EVAP system pressure by watching the fuel tank pressure (FTP) sensor. When the sensor indicates a small leak in the EVAP system, this code is set.
Related evaporative emission trouble codes include P0450, P0451, P0452, P0453, P0454, P0455, P0457, P0458, and P0459.
Possible Causes P0456
1
A small leak in any of the EVAP hoses or fuel tank hoses
2
A small leak in the purge valve or vent valve
3
The EVAP Canister may be leaking
Solutions & Repair Steps P0456
First, using a scan tool activate the vent solenoid, sealing the system. Then monitor the fuel tank pressure (FTP) sensor.
If the system is sealing properly, the number will stay consistent. If is isn't, the pressure sensor will show that as well.
If the system slowly leaks, use a smoke machine and watch for smoke exiting the system at any EVAP component. Any where there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air pressure. Doing so can damage the purge and vent solenoids in the system.
Other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0444 - P0445 - P0446 - P0447 - P0448 - P0449 - P0452 - P0453 - P0455
If the system is sealing properly, the number will stay consistent. If is isn't, the pressure sensor will show that as well.
If the system slowly leaks, use a smoke machine and watch for smoke exiting the system at any EVAP component. Any where there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air pressure. Doing so can damage the purge and vent solenoids in the system.
Other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0444 - P0445 - P0446 - P0447 - P0448 - P0449 - P0452 - P0453 - P0455
Related Codes
P0450
Evap Emission System Pressure Sensor Malfunction
P0451
Evap Emission System Pressure Sensor Performance
P0452
EVAP Pressure Sensor/Switch Low
P0453
Evaporative Emissions Control System Pressure Sensor High Input
P0454
Evap Emission System Pressure Sensor Intermittent
P0455
Evap System Large Leak Detected
P0457
Evaporative Emission Control System Leak Detected
P0458
EVAP Emission System Purge Control Valve Circuit Low
P0459
EVAP Emission System Purge Control Valve Circuit High