Toronado V6-231 3.8L (1986)
Wiring Diagram for Chart C-3 - Canister Purge System
CHART C-3 - CANISTER PURGE SYSTEM
Circuit Description:
Canister purge is controlled by a normally closed solenoid that allows throttle body vacuum to purge the canister vapors when energized. Ignition supply
voltage is applied to solenoid terminal "A" through CKT 139 and the ECM completes the circuit to ground through CKT 428 to energize the solenoid
(purge "ON").
If the service diagnostics output EO01 is entered with the engine stopped, the ECM will cycle the canister purge solenoid "ON" and "OFF" at the three
second intervals.
During normal operation the vapor canister will be purged when:
a. Engine coolant temperature is over 63°C (145°F).
b. After the engine has been running 30 sec.
c. Vehicle is traveling over 7 mph.
d. TPS is geater than .73 volts
e. Engine is operating in "Closed Loop" mode and is not in decelerating mode (fuel shutoff mode).
Test Description:
The following numbered steps correspond with the step numbers on the diagnostic chart.
1.
Checks for proper solenoid operation and control by ECM. If no error in operation found, the problem must be vacuum related.
2.
Verifies ignition supply voltage to the solenoid terminal "A".
3.
If the ECM is controlling the path to ground through CKT 428 the test light will cycle "ON" and "OFF" every three seconds.
4.
Solenoid coil resistance must measure more than 20 ohms. Less resistance could result in an early failure of the ECM. Using an ohmmeter, check
the purge solenoid and low speed coolant fan relay resistances before installing a replacement ECM, because they could cause failure of the purge
circuit quad-driver.
5.
Verifies positive control of vacuum by purge solenoid and checks for leaks.
