• | 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. |
Circuit | Short to Ground | High Resistance/Open | Short to Voltage | Signal Performance |
---|---|---|---|---|
Ignition 1 Voltage - Purge Supply | P0443 | P0443 | -- | -- |
Battery Positive - Vent Supply | P0449 | P0449 | -- | -- |
EVAP Purge Solenoid Control | P0443 | P0443 | P0443 | -- |
EVAP Vent Solenoid Control | P0449 | P0449 | P0449 | -- |
An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The engine control module (ECM) grounds the EVAP canister purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The EVAP canister purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.
Battery voltage is supplied to the EVAP canister vent solenoid valve. The ECM grounds the EVAP canister vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the EVAP canister vent solenoid valve as ON or OFF.
• | The ignition is ON. |
• | The system voltage is between 11-18 volts. |
• | DTCs P0443 and P0449 run continuously when the above conditions are met. |
The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match, for a minimum of 6 seconds.
DTCs P0443 and P0449 are Type B DTCs.
DTCs P0443 and P0449 are Type B DTCs.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the EVAP canister purge solenoid. |
⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for engine control module (ECM) replacement, setup, and programming |