Aston Martin diagnostic trouble code
P0457: Evaporative Emission System Leak Detected (fuel cap loose/off)
Use this reference to understand the recorded condition, confirm the available V8 Vantage or DB9 manual coverage, and follow the documented diagnostic checks before replacing parts.
- Code family
- Powertrain
- Vehicle system
- Emissions and EVAP
- Manual coverage
- DB9
- Warning-lamp status
- DB9: MIL
What Aston Martin code P0457 means
Evaporative Emission System Leak Detected (fuel cap loose/off)
DB9 preliminary diagnostic manual · section 2-108
Manufacturer fault-analysis procedure
Manual fault definition
P0457 - Unable to hold tank vacuum (gross leak)
fuel filler cap off or loose.
fuel filler cap off or loose.
Cautions and notes
NOTE: The integrity of the vapour recovery system is
checked by closing the canister vent valve, opening the
vapour management valves and applying a vacuum
from the inlet manifold. When the fuel tank vacuum is
at an appropriate level, the VMVs are closed.
The vacuum in the closed vapour recovery system may
then be monitored using the fuel tank pressure transducer.
checked by closing the canister vent valve, opening the
vapour management valves and applying a vacuum
from the inlet manifold. When the fuel tank vacuum is
at an appropriate level, the VMVs are closed.
The vacuum in the closed vapour recovery system may
then be monitored using the fuel tank pressure transducer.
Test sequence and decision path
1. Check the security and sealing of the fuel filler
cap.
If any defect is identified, service/replace the cap
as necessary. Run the leak test again to ensure
that the problem is resolved.
If no obvious defect is identified, go to step 2.
2. Run the evaporative loss system leak test to confirm the severity of the leak.
3. Visually examine the filler neck pipes for disconnected/split hoses and connectors.
If any defect is identified, service/replace as necessary. Run the leak test again to ensure that the
problem is resolved.
If no defect is identified, go to step 4.
4. WARNING: Do not apply a pressure or vacuum
greater than 14.0 inches H
2O (34.8 kPa) to the
fuel system. Excessive pressure may blow a connection. Excessive vacuum can collapse the fuel
tank.
Connect an Evaporative Emissions Tester to the
schreader valve near the vapour management
valves.
Plug the canister vent outlet in the fuel filler well.
Apply a pressure of 14 in H2O (34.8 kPa) and
monitor the pressure reading.
If no leak is detected, go to step 4.
If the pressure drops rapidly, locate the leak using
the ultrasonic leak detector.
If any leak is identified, service the system as necessary. Remove the plug from the canister vent
outlet in the filler well. Run the leak test again to
ensure that the problem is resolved.
5. Assemble the break-out box to the primary PCM.
Key on. Energise the canister vent valve using the
WDS Output State Control function. Have a colleague hold the valve whilst toggling the valve on
and off
If the valve does not energise/deenergise, disconnect the valve and check the 12volts VPWR and
the ground circuits for continuity.
If continuity is good, replace the canister vent
valve.
If a continuity defect is identified, service the circuits as necessary and run the leak test again to
ensure that the problem is resolved.
Open the corresponding manual page for wiring diagrams and figures
cap.
If any defect is identified, service/replace the cap
as necessary. Run the leak test again to ensure
that the problem is resolved.
If no obvious defect is identified, go to step 2.
2. Run the evaporative loss system leak test to confirm the severity of the leak.
3. Visually examine the filler neck pipes for disconnected/split hoses and connectors.
If any defect is identified, service/replace as necessary. Run the leak test again to ensure that the
problem is resolved.
If no defect is identified, go to step 4.
4. WARNING: Do not apply a pressure or vacuum
greater than 14.0 inches H
2O (34.8 kPa) to the
fuel system. Excessive pressure may blow a connection. Excessive vacuum can collapse the fuel
tank.
Connect an Evaporative Emissions Tester to the
schreader valve near the vapour management
valves.
Plug the canister vent outlet in the fuel filler well.
Apply a pressure of 14 in H2O (34.8 kPa) and
monitor the pressure reading.
If no leak is detected, go to step 4.
If the pressure drops rapidly, locate the leak using
the ultrasonic leak detector.
If any leak is identified, service the system as necessary. Remove the plug from the canister vent
outlet in the filler well. Run the leak test again to
ensure that the problem is resolved.
5. Assemble the break-out box to the primary PCM.
Key on. Energise the canister vent valve using the
WDS Output State Control function. Have a colleague hold the valve whilst toggling the valve on
and off
If the valve does not energise/deenergise, disconnect the valve and check the 12volts VPWR and
the ground circuits for continuity.
If continuity is good, replace the canister vent
valve.
If a continuity defect is identified, service the circuits as necessary and run the leak test again to
ensure that the problem is resolved.