1. Ken Periman Problem solving, Large leak failure in vehicle.

2. Problem Statement
Large leak failure in vehicle.

3. Initial investigation
A vehicle was found to have a code that identified a large vapor leak in the fuel loop system. The leak was investigated as a potential fuel tank, fuel line, or canister leak. The fuel tank was found to have no issues and the fuel lines were not an issue. The canister did have an issue. Upon further investigation there were other codes that identified that the canister was the issue. Original investigation into the canister reveled a crack in the canister housing where they perform a sonic weld. The concern was that the crack was present again and the company did not maintain containment.
Air flows through the solenoid of the canister. The red box indicates the area of concern.
Side View of solenoid on canister.

4. Investigation Good Condition part
Front view of good part. There should be a gasket on the plunger and there should be a spring holding the plunger up in the solenoid.
Plunger
Gasket
Spring
Air Flow
Front View drawing
Chamber
Chamber is sealed
by gasket on plunger
No air flow can
enter chamber
Open Position
Closed Position
Good Condition part

5. Investigation Defective part Because gasket is lodged into
Front view of part with issue. There is a gap where the seal should be. This would cause allot of air to pass through causing an error code of P0455 (Large air leak).
Defective part
Because gasket is lodged into
chamber the plunger cannot seal
the chamber and allows air flow
into the chamber.
Gasket is partially lodged in chamber and blocking spring from returning to proper position

6. Findings
Due to the initial issue of a cracked canister and a leak failure the Tier 2 supplier performed an added inspection that would confirm no leak. The problem was that due to the added inspection, the sub supplier didn’t realize that the action was actually causing this issue.

7. Discovery:
Initial assumption from Quality team was that the canister was leaking at the sonic weld and that the supplier had allowed the containment to break and we had dirty product again.
What really happened is the sub supplier was checking for leaking canisters due to this concern by applying air pressure to the canister via the solenoid and dipping the canister in water to look for air escapement. The supplier’s quality member after checking for air leaking would release the pressure improperly and the sudden rush of air back through the solenoid in the opposite direction actually separated the gasket from the plunger and usually lodged the gasket into the lower chamber.
The supplier trying to confirm quality through an extra not fully tested inspection caused the canister fail in a similar way as the original issue identified.