P0496

DTC P0496

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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-Purge

Circuit/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 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.

Conditions for Running the DTC

* DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0128, P0442, P0443, P0446, P0449, P0452, P0453, 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 less than 30°C (86°F).
* The start-up IAT is less than 30°C (86°F).
* The intake air temperature (IAT) is between 4-30°C (39-86°F).
* The start-up ECT and IAT are within 8°C (14°F) of each other.
* 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.
* The FTP sensor is more than -10 inches H2O for 60 seconds.

Action Taken When the DTC Sets

DTC P0496 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P0496 is a Type B DTC.

* Scan Tool Output Controls

Circuit/System Verification

1. Start the engine.
2. Seal the EVAP system using the Purge/Seal function with a scan tool.
3. 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: Circuit/System Verification must be performed before proceeding.

1. Disconnect the EVAP purge pipe from the EVAP canister purge solenoid valve.
2. Start the engine.
3. Observe the FTP sensor with a scan tool.

• If the Fuel Tank Pressure Sensor parameter is less than 1.7 volts, replace the EVAP canister purge solenoid valve.
• If the Fuel Tank Pressure Sensor parameter is greater than 1.7 volts, replace the FTP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Fuel Tank Pressure Sensor Replacement
* Evaporative Emission Canister Purge Solenoid Valve Replacement.