P1441

P1441 is GM's EVAP System Flow During Non-Purge — the ECM monitors the EVAP canister purge valve and expects ZERO purge flow when the purge command is at 0% (engine off, cold start, or during diagnostic monitor windows), but it detected vacuum drawing through the EVAP system anyway, indicating a purge valve stuck partially open. Commanded purge runs 0-100% duty cycle depending on engine operating conditions; the ECM enables purge once coolant temp is above ~160F and slowly ramps duty cycle up to allow stored fuel vapor from the charcoal canister to be drawn into the intake and burned. A stuck-open or leaking-past purge valve creates an uncommanded vacuum leak that the ECM detects either by monitoring fuel trim shifts at idle or by running an active EVAP test (sealing the system and watching pressure decay). Cheapest-first ladder: (1) Scan live data and watch commanded purge percentage at hot idle — it should sit at 0% for several minutes after a cold start and only ramp up once closed-loop is active; if you see fuel trims swinging when commanded purge is 0%, the valve is leaking through. (2) Pull the purge valve and apply hand-vacuum across it with the connector unplugged — it should hold vacuum indefinitely; if it bleeds down in under 30 seconds, it's stuck open. (3) Inspect the EVAP lines from the purge valve to the intake for cracked rubber or fuel-soaked vapor lines (especially on trucks 100k+ miles where the rubber sections at the canister and intake harden). (4) Replace the purge valve ($35-$75 AC Delco) — these are not serviceable. (5) On older trucks, verify the canister itself isn't saturated from a previous overfilled-tank event — a saturated canister can also drag fuel through to the intake even with a good valve. Don't replace the canister or the gas cap before testing the purge valve in isolation — the purge valve is the single most common P1441 cause on GM platforms and a $50 part fixes 80%+ of cases.

Vehicle-specific patterns: 1996-2005 Silverado / Tahoe / Suburban / Sierra / Yukon with the early Vortec 4.3/4.8/5.3/6.0 — the purge valve mounts to the top of the intake manifold or on a bracket near the throttle body, gets cooked by engine heat, and the internal diaphragm cracks; this is the most common P1441 vehicle in North American shops. 2005-2010 Cobalt / G5 / HHR / Ion with the 2.2/2.4 Ecotec throws P1441 from a known stuck purge valve and from cracked plastic vent lines at the rear of the engine. 2010+ Equinox / Terrain / Malibu with the 2.4L LAF/LEA Ecotec and 2010+ Camaro / CTS / Traverse with the LFX/LLT 3.6L V6 throws P1441 less commonly but when it does, it's often a cracked EVAP line at the firewall pass-through rather than the valve itself. 2003-2007 Silverado HD with the LB7/LLY Duramax doesn't use a typical gasoline-style EVAP system, so P1441 doesn't apply to those diesel platforms; on the gas HD trucks of the same era (Vortec 6.0L L18), the failure mode matches the light-duty Vortec. Estimated repair: $50 (purge valve DIY) to $260 (purge valve + cracked vapor line + canister vent solenoid on a high-mileage Silverado).