Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0496: Evaporative Emission System Flow During Non-PurgeCircuit/System Description
This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve OFF and the EVAP canister vent solenoid valve ON. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets. The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.
Control Module Command | EVAP Canister Purge Solenoid Valve | EVAP Canister Vent Solenoid Valve |
|---|---|---|
ON | Open | Closed |
OFF | Closed | Open |
Conditions for Running the DTC
| • | DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0128, P0442, P0443, P0446, P0449, P0452, P0453, P0445, P1106, P1107, P1111, P1112, P1114, P1115, P1516 are not set. |
| • | The ignition voltage is between 10-18 volts. |
| • | The barometric pressure (BARO) is more than 74 kPa. |
| • | The fuel level is between 15-85 percent. |
| • | The engine coolant temperature (ECT) is between 4-30°C (39-86°F). |
| • | The intake air temperature (IAT) is between 4-30°C (39-86°F). |
| • | The start-up ECT and IAT are within 9°C (16°F) of each other. |
| • | The vehicle speed sensor (VSS) is less than 121 km/h (75 mph). |
| • | The FTP sensor is less than -2.5 inches H2O at ignition ON. |
| • | DTC P0496 runs once per cold start for 96 seconds. |
Conditions for Setting the DTC
The control module detects vacuum during a non-purge condition.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
- Start the engine.
- Seal the EVAP system using the Purge/Seal function with a scan tool.
- Observe the FTP sensor with a scan tool. The Fuel Tank Pressure Sensor parameter should be less than 1.7 volts.
Circuit/System Testing
Important: Perform the Circuit/System Verification before proceeding with the Circuit/System Testing.
Disconnect the EVAP purge pipe from the EVAP canister purge solenoid valve.
| ⇒ | If the Fuel Tank Pressure Sensor parameter is less than 1.7 volts, replace the EVAP canister purge solenoid valve. |
| ⇒ | If the pressure is greater than 1.7 volts, replace the FTP sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
