Vehicle: 2018 Toyota Corolla, L4-1.8L (2ZR-FAE), Manual Transmission/Transaxle

Mileage: 368,473

Problem: An illuminated malfunction indicator light (MIL) was why this Corolla was brought to the shop. The owner said the car ran fine.

Case Details: When the technician connected a scan tool, he found diagnostic trouble code (DTC) P0441 - Evaporative Emission Control System Incorrect Purge Flow.

He replaced the purge solenoid valve and the leak detection pump, but the DTC came back almost immediately. Next, he smoke-tested the evaporative system and found a small leak coming from the leak detection pump even when it was commanded closed. It was time to call ALLDATA Tech-Assist.

The Tech-Assist consultant advised that a small leak in the leak detection pump is normal since there is a calibration port in it. An effective testing method is to physically block the pump port then check for leaks.

He also advised checking to see if the canister was broken up or saturated, especially considering the vehicle’s high mileage.

The technician checked the canister first and found it was very heavy. It was saturated with water.

Confirmed Repair: He replaced the complete canister assembly, cleared the DTC and performed a specific “drive cycle” on the test drive to set evaporative monitors to complete status. The MIL stayed off and there were no further issues. Problem solved!