Circuit Description
The evaporative system draws stored fuel vapors from the charcoal canister.
The canister purge solenoid is used to control the flow of vapors from the canister
to the intake manifold. The PCM controls the solenoid with a pulse width modulated
(PWM) signal. The PCM uses a generic field effect transistor driver (GFD) to control
the solenoid ground when certain conditions have been met. The GFD driver has the
capability to diagnose if the circuit has opened or shorted.
Conditions for Setting the DTC
DTC P0443 will set if the feedback signal voltage is:
| • | Above 0.3 volts when the solenoid is commanded ON |
| • | Below 7 volts when the solenoid is commanded OFF |
Diagnostic Aids
| • | An intermittent open or short in the harness will result in a DTC P0443.
Intermittent conditions can be detected by using a scan tool and observing the purge
feedback status. The status should be high when the solenoid is commanded OFF, and
low when the solenoid is commanded ON. |
| • | Solenoid resistance is 19-31 ohms. |
| • | Check the 10 amp EGR fuse in the UHJB. |
