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What the 12597567 EVAP Purge Solenoid Valve Does

The 12597567 Vapor EVAP Emission Canister Purge Solenoid Valve is a direct-fit GM OEM-specification part for Chevrolet, Buick, GMC, and Cadillac light-duty platforms. It is a normally-closed, pulse-width modulated (PWM) solenoid that meters fuel vapor from the charcoal canister into the intake manifold under ECU command.

The coil reads 25 to 35 Ω at 20°C on a nominal 12V DC circuit. A high-temperature thermoplastic body and nickel-plated blade terminals survive underhood temperatures above 140°C. For 2026 the valve stays compliant with SAE J1979-3 OBD-II protocols, ISO 14229-1 UDS diagnostic services, and EPA Tier 4 / CARB ACC II evaporative emission mandates.

DTC Codes This Valve Addresses

Circuit faults (P0443, P0444, P0445) and stuck-open flow (P0496) are primary fixes. P0446 and P0449 belong to the vent valve side, so treat this purge solenoid as a secondary suspect there. P0455 becomes addressable once you rule out hoses and the canister. P144C is covered as secondary overlap.

Full Technical Specifications

Two more facts worth knowing: the 9 to 16V input tolerates 48V mild-hybrid buses on an isolated circuit, and the connector matches GM Global B architecture.

Verified Engine Coverage

Confirmed RPO families include the 3.6L V6 DOHC engines (LY7, LLT, LFX) in the Equinox, Traverse, Malibu, Enclave, and LaCrosse, plus Gen IV V8s: 5.3L (LM7, LC9, LH6) in the Silverado 1500, Tahoe, and Suburban, 6.0L hybrid (LFA, LZ1), 6.2L (L9H, L94) in the Silverado 1500 and Yukon Denali, and the 6.0L HD L96 in Silverado 2500HD/3500HD.

What Changed for Model Year 2026

SAE J1979-3 was ratified in Q4 2025 and tightens EVAP monitor rationality thresholds. The allowable 0.020" leak detection orifice correlation window narrowed from ±15% to ±10% for Model Year 2026 and forward.

The 12597567 holds flow linearity within ±3% of the GM-specified 22 L/min at 40 kPa ΔP benchmark across the 30% to 70% PWM duty-cycle window, well inside the new corridor.

EPA Tier 4 Leak Detection

Tier 4 standards, phased in from 2024 through 2027, mandate a 0.020" leak detection threshold with under 2% false-pass tolerance on light-duty EVAP systems. That is a 30% tightening from the previous 0.040" standard. A marginal solenoid that passed at 0.040" can now set P0455 (large leak) or P0442 (small leak).

The 12597567 answers this with a precision-machined pintle seat that seals hermetically at 0 kPa differential, below 0.005 SCCM helium leak rate at 1 atm ΔP. That clears the 2026 threshold with more than 4× safety margin and supports I/M 240 readiness monitor completion.

Build Materials

The diaphragm is a peroxide-cured FKM terpolymer with 68% fluorine content. It resists ethanol-blended fuel vapors from E10 to E85 plus hydrocarbons including toluene, benzene, and xylene. ASTM D471 validation (Reference Fuel C, 70 hours at 23°C) shows under 5% volume swell.

The glass-reinforced PPS body meets SAE J2809 Class B underhood durability criteria and ISO 6722-1 thermal classification for continuous 150°C exposure. Nickel-plated terminals conform to SAE/USCAR-21 Revision 3: 96 hours salt spray, no red rust.

Inside, the pintle seat is 316L stainless steel with a diamond-like carbon (DLC) coating. Stiction hysteresis stays below 2% of full-scale actuation in the 10 Hz PWM loop used by GM's E38, E67, and E92 ECM families.

2026 Failure Symptoms on Global B Vehicles

A failing purge solenoid on GM Global B (VIP) architecture shows up in specific ways:

• Intermittent P0496 with freeze-frame data showing -0.8 to -1.2 kPa FTP sensor deviation at idle.
• Rough idle after hot-soak refueling, caused by fuel vapor flooding.
• U18A2 lost-communication DTC between the ECM and the FPDM (Fuel Pump Driver Module), triggered when EVAP-induced fuel tank pressure anomalies push the vehicle into limp-home mode.
• A "Service Emissions System" message on the DIC with an active P0443 circuit rationality failure during the new SAE J1979-3 continuous monitor.

The 2026 monitor samples purge flow every 200 ms instead of the legacy 500 ms. Intermittent solenoid stiction is therefore far easier to catch than on pre-2026 vehicles.

How to Test the Valve Before You Replace It

Electrical: measure resistance across the terminals. The correct reading is 25 to 35 Ω at 20°C. An open circuit or a short below 5 Ω confirms failure.

Mechanical: apply 12V DC and listen for an audible click. With no voltage applied, blow through the valve: a healthy normally-closed unit stays fully sealed. With 12V applied, air passes freely.

Scan tool: use GDS2 or MDI 2 with GM SPS2 to command EVAP purge duty from 0% to 100% in 10% steps while watching FTP sensor voltage. If FTP voltage lags the commanded duty by more than 500 ms, the solenoid is stuck or sluggish and needs replacement.

P0446 and the Vent Valve Question

P0446 (EVAP Vent System Performance) points at the vent solenoid first. That valve sits near the charcoal canister at the fuel tank, so start your diagnosis there.

The purge valve still creates an indirect failure path. A solenoid stuck open prevents the EVAP system from building the vacuum needed for the 0.020" engine-off natural vacuum (EONV) leak detection test.

If you already replaced the vent solenoid and P0446 persists, test the purge valve for an internal leak. If it fails the normally-closed seal test, the 12597567 EVAP purge solenoid is the recommended replacement.

Installation Steps and Torque Specs

1. Disconnect the negative battery terminal.
2. Locate the purge solenoid on the intake manifold or engine bracket.
3. Depress the quick-connect tabs and remove the EVAP vapor line.
4. Disconnect the 2-pin GT 150 electrical connector.
5. Remove the bracket bolt with a 10mm socket and reinstall at 10 N·m (89 lb-in).
6. Reverse the steps to install.

No ECM relearn is required. Purge adaptives reset automatically within three drive cycles.

2026 note: GM Global B vehicles can display a pending DTC for up to 3 key cycles after installation. The ECM re-learns purge flow characteristics during this period, and the pending code clears on its own.

For deeper EVAP diagnostics, GM service bulletin 08-06-04-019G covers the system in its latest revision.

Where to Buy the 12597567 and How to Reach Support

Koeep carries this valve under three catalog entries. The main listing is the 12597567 Vapor EVAP Emission Canister Purge Solenoid Valve for Chevy and Buick fitment.

For GMC-inclusive fitment, use the 12597567 EVAP Emisson Canister Vapor Purge Solenoid Valve fits Chevy Buick GMC page. A third entry, the 12597567 EVAP Emisson Vapor Canister Solenoid Purge Valve For Chevy Buick, carries the same valve with the same specs.

Need engine-side hardware as well? Browse the Engines & Engine Parts collection for the wider catalog. Rebuilding an older truck too? The Complete Suspension Front Ball Joint Pitman Idler Arm Kit guide covers steering parts for Chevy and GMC C2500/C3500 platforms.

Frequently Asked Questions