Circuit Description
This diagnostic monitors the evaporative emission (EVAP) system for faults in the purge solenoid electrical circuit. An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid. The EVAP canister purge solenoid is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module monitors the status of the driver. The control module controls the EVAP canister purge solenoid ON time by grounding the control circuit via an internal switch called a driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0443 Evaporative Emission (EVAP) Purge Solenoid Control Circuit
Conditions for Running the DTC
| • | DTCs P0442, P0496, P0498, and P0499 are not set. |
| • | The engine is running. |
| • | The battery voltage is 10 volts. |
| • | The control module has commanded the purge solenoid ON and OFF at least once during the ignition cycle. |
| • | DTC P0443 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
| • | The control module detects that the commanded state of the driver and the actual state of the control circuit Do NOT match. |
| • | The above conditions are present for a minimum of 5 seconds. |
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. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests if the concern is active. The EVAP purge solenoid is pulse width modulated (PWM). Clicking should be heard or felt when the purge solenoid is commanded to 20 percent and should stop when the EVAP purge solenoid is commanded to 0 percent. The rate at which the solenoid cycles should increase as the commanded state is increased and decreased as the commanded state is decreased. Repeat the commands as necessary.
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This step tests if a ground is constantly being applied to the EVAP purge solenoid.
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This step verifies that the control module is providing ground to the EVAP purge solenoid.
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After replacing the PCM, a new minimum throttle position and idle speed must also be established.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Do you hear or feel a clicking from the EVAP purge solenoid when the solenoid is commanded to 20 percent? | Go to Step 3 | Go to Step 4 | |
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 6 | |
Command the EVAP purge solenoid to 20 percent with a scan tool. Does the test lamp illuminate or pulse when the EVAP purge solenoid is commanded to 20 percent? | Go to Step 9 | Go to Step 7 | |
7 | Test the control circuit of the EVAP purge solenoid for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs . 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 for a short to ground. Refer to Circuit Testing and Wiring Repairs . 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. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 . 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. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 14 | -- |
12 | Replace the EVAP purge solenoid. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | Go to Step 14 | -- |
Did you complete the replacement? | Go to Step 14 | -- | |
14 |
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? | System OK | |
