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Home >> Buick >> 2004 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (DTC P0140 To P0496) >> Engine Controls Diagnosis >> DTC P0443 >> Test Description
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Test Description

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

  1. 2:  This step tests if the concern is active. The EVAP purge solenoid valve is pulse width modulated (PWM). Clicking should be heard or felt when the purge solenoid valve is commanded to 50 percent and should stop when the EVAP purge solenoid valve is commanded to 0 percent. The rate at which the valve cycles should increase as the commanded state is increased and decreased as the commanded state is decreased.
  2. 5:  This step tests if a ground is constantly being applied to the EVAP purge solenoid valve.
  3. 6:  This step verifies that the control module is providing ground to the EVAP purge solenoid valve.
DTC P0443

Step Action Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 
  1. Turn ON the ignition, with the engine OFF.
  2. Command the EVAP purge solenoid valve to 50 percent and then to 0 percent with a scan tool.
Do you hear or feel a clicking from the EVAP purge solenoid valve when the valve is commanded to 50 percent?		 Go to Step 3  Go to Step 4 
3
  1. Observe the Freeze Frame/ Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Turn ON the ignition, with the engine OFF.
  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 4  Go to Intermittent Conditions
4
  1. Turn OFF the ignition.
  2. Disconnect the EVAP purge solenoid valve.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 1 voltage circuit of the EVAP purge solenoid with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 5  Go to Step 11 
5 
  1. Connect a test lamp between the control circuit of the EVAP purge solenoid valve and the ignition 1 voltage circuit of the EVAP purge solenoid valve.
  2. Command the EVAP purge solenoid valve to 0 percent with a scan tool.
Does the test lamp illuminate?		 Go to Step 8  Go to Step 6 
6  Command the EVAP purge solenoid valve to 50 percent with a scan tool.
Does the test lamp illuminate or pulse when the EVAP purge solenoid valve is commanded to 50 percent?		 Go to Step 9  Go to Step 7 
7 Test the control circuit of the EVAP purge solenoid valve for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 14  Go to Step 10 
8 Test the control circuit of the EVAP purge solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 14  Go to Step 13 
9 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 in Wiring Systems.
Did you find and correct the condition?		 Go to Step 14  Go to Step 12 
10 Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 14  Go to Step 13 
11 Repair the open or short to ground in the ignition 1 voltage circuit of the EVAP purge solenoid valve. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 14  -
12 Replace the EVAP purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement .
Did you complete the replacement?		 Go to Step 14  -
13 Replace the control module. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 Go to Step 14  -
14
  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 15 
15 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 Go to Diagnostic Trouble Code (DTC) List System OK
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