EVAP System Leak Test and Smoke Test Procedure Checklist

This EVAP system leak test and smoke test checklist provides systematic diagnosis of evaporative emission control faults - the most common check engine light cause. EVAP leaks emit hydrocarbon vapors and cause OBD-II monitor failures preventing emissions tests. Aligned with EPA OBD-II EVAP monitor standards, CARB enhanced evaporative emission requirements, and SAE J1699 OBD-II test procedure standards.

Industry: Automotive Service
Frequency: Per Check Engine Light / Per Emissions Test Failure
Estimated Time: 30-60 minutes
Role: ASE A8 Engine Performance Technician
Total Items: 27
Compliance: EPA OBD-II EVAP Monitor Standards (40 CFR Part 86), CARB Enhanced Evaporative Emission Requirements, SAE J1699 OBD-II System Test Standards, EPA Emission Control Warranty (8 yr/80,000 mi), ASE A8 Engine Performance Certification

Basic EVAP Checks Before Smoke Test

Rule out obvious causes before using smoke machine.

Fuel cap tightened correctly and tested for seal integrity with hand pump?
EVAP OBD-II monitor status reviewed - confirmed Not Ready or flagging?
Fuel level between 1/4 and 3/4 tank for EVAP monitor drive cycle?
Vehicle not refueled within 1 hour - recent fueling causes false EVAP faults?
No strong fuel odor from canister indicating saturated charcoal from tank overfill?

Smoke Machine Leak Detection

Locate EVAP system leaks with smoke under low pressure.

EVAP vent valve commanded CLOSED via bi-directional test before introducing smoke?
Smoke introduced at correct port at maximum 1-2 PSI?
All EVAP lines, hoses, and T-connections inspected for smoke emergence?
Charcoal canister body and all hose connections inspected for smoke leaks?
Leak location identified, documented with photo, and repair quoted?
Fuel tank area including filler neck, fuel pump module, and tank seams checked?

Purge and Vent Valve Testing

Test EVAP control valve operation.

Purge valve tested bi-directionally - opens when commanded, holds vacuum when closed?
Purge valve confirmed NOT open at idle - stuck open purge causes rich condition and stall?
Vent valve tested - opens normally and closes on command (P0446 indicates stuck open)?
Fuel tank pressure sensor reading plausible - slightly negative at rest, changes during purge?
Charcoal canister not saturated with liquid fuel from chronic tank overfilling?

Repair and Monitor Completion Verification

Repair leaks and verify EVAP monitor runs to Ready status.

All identified leaks repaired with correct OEM-spec replacement components?
Post-repair smoke test confirms system holds pressure with no visible leaks?
All EVAP codes cleared after repair?
EVAP OBD-II monitor run to READY status confirming successful repair?
Customer advised vehicle now ready for emissions testing?

Warranty and Documentation

Check emission warranty and document all EVAP service.

EVAP component warranty checked - EPA requires 8 yr/80,000 mi on canister, purge valve, and FTP sensor?
Warranty claim filed with OEM if components qualify?
EVAP service documented with codes, leak location, repair, and post-repair smoke test result?
Customer advised to never top off fuel tank after pump click to prevent canister saturation?
If fuel cap replaced - new part number documented on RO?
Customer advised of state emissions testing schedule if applicable?

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Why Use This EVAP System Leak Test and Smoke Test Procedure Checklist?

This evap system leak test and smoke test procedure checklist helps automotive service teams maintain compliance and operational excellence. Designed for ase a8 engine performance technician professionals, this checklist covers 27 critical inspection points across 5 sections. Recommended frequency: per check engine light / per emissions test failure.

Ensures compliance with EPA OBD-II EVAP Monitor Standards (40 CFR Part 86), CARB Enhanced Evaporative Emission Requirements, SAE J1699 OBD-II System Test Standards, EPA Emission Control Warranty (8 yr/80,000 mi), ASE A8 Engine Performance Certification, UK MOT EVAP Standards, India CMVR BS VI Evaporative Emission Requirements. Regulatory-aligned for audit readiness and inspection documentation.

Frequently Asked Questions

What does the EVAP System Leak Test and Smoke Test Procedure Checklist cover?

This checklist covers 27 inspection items across 5 sections: Basic EVAP Checks Before Smoke Test, Smoke Machine Leak Detection, Purge and Vent Valve Testing, Repair and Monitor Completion Verification, Warranty and Documentation. It is designed for automotive service operations and compliance.

How often should this checklist be completed?

This checklist should be completed per check engine light / per emissions test failure. Each completion takes approximately 30-60 minutes.

Who should use this EVAP System Leak Test and Smoke Test Procedure Checklist?

This checklist is designed for ASE A8 Engine Performance Technician professionals in the automotive service industry. It can be used for self-assessments, team audits, and regulatory compliance documentation.

Can I download this checklist as a PDF?

Yes, this checklist is available as a free PDF download. You can also use it digitally in the POPProbe mobile app for real-time data capture, photo documentation, and automatic reporting.