DTC P0441 - EVAP SYSTEM NO FLOW DURING PURGE Pontiac Firebird IV

Note. For circuit reference, see the appropriate WIRING DIAGRAMS article. For connector and terminal identification, see CONNECTOR IDENTIFICATION .

Circuit Description

Evaporative (EVAP) emission canister purge is controlled by a solenoid valve which allows ported vacuum to purge canister when energized by PCM. A vacuum switch in purge line is used to detect when system is being purged. PCM supplies and reads a 5-volt reference to switch. If switch is closed (no purge detected) when commanded by PCM, DTC P0441 is set.

Conditions required to set DTC are

1. No ECT, IAT, MAF, MAP, TP sensor DTCs set.
2. BARO greater than 10 psi (0.7 kg/cm 2 ).
3. ECT less than 237°F (114°C).
4. IAT less than 158°F (70°C).
5. Difference between ECT and IAT less than 18°F (10°C).
6. Engine speed 550-5000 RPM.
7. Canister Pulse Width Modulation (PWM) greater than 75 percent.
8. EVAP vacuum switch remains closed (12-volt signal at PCM).
9. TP sensor indicates throttle position between 2.5-52 percent.
10. MAP greater than 10 kPa.
11. Listed conditions present greater than 4 seconds.