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Home >> Chevrolet >> 2005 >> Classic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTC P0301-P2401) >> Diagnostic Information & Procedures >> DTC P0496 >> Test Description
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Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  This step inspects for a leaking EVAP purge solenoid valve.
  2. 4:  Removing the fuel fill cap will equalize the pressure inside the tank with atmospheric pressure. At 0 inches of H2O the FTP sensor should be near 1.5 volts. If the sensor is not, there is a concern with the sensor or related wiring.
DTC P0496

Step Action Values Yes No
Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram and Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Disconnect the purge pipe from the evaporative emission (EVAP) purge solenoid valve.
  2. Install a hand held vacuum gage to the EVAP purge solenoid valve purge port.
  3. Disconnect the EVAP purge solenoid valve harness connector.
  4. Monitor vacuum on the vacuum gage.
  5. Start the engine and allow the engine to idle.
  6. Increase the idle to 1,200-1,500 RPM.
Does the vacuum gage indicate an increase in vacuum?		 - Go to Step 9  Go to Step 3 
3
  1. Connect the EVAP purge solenoid valve harness connector.
  2. Monitor vacuum on the vacuum gage.
  3. Increase the idle to 1,200-1,500 RPM.
Does the vacuum gage indicate an increase in vacuum?		 - Go to Step 5  Go to Step 4 
4 
  1. Turn OFF the ignition.
  2. Remove and then install the fuel fill cap.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the Fuel Tank Pressure Sensor parameter with a scan tool.
Is the Fuel Tank Pressure Sensor parameter within the specified value?		 -0.5 to +0.5 in H2O Go to Diagnostic Aids Go to Step 8 
5 Test the EVAP purge solenoid valve control circuit for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs .
Did you find and correct the conditions?		 - Go to Step 11  Go to Step 6 
6 Test for an intermittent and for a poor connection at the EVAP purge solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 11  Go to Step 7 
7 Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 11  Go to Step 10 
8 Replace the fuel tank pressure (FTP) sensor. Refer to Fuel Tank Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 11  -
9 Replace the EVAP purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement .
Did you complete the replacement?		 - Go to Step 11  -
10 Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 11  -
11
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 12 
12 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle System OK
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