Symptoms
A rough or uneven idle, hesitation under load, difficulty starting, warning lamps, and in the case the recall is written around, the engine stopping while the car is moving.
Likely cause
The impeller is the part that moves fuel inside the tank. Denso's own recall states that it “may crack and deform, potentially causing the fuel pump to fail”. The regulator's filings do not go further than that, and neither does this file: the several explanations circulating for why the impeller deforms are not in any document that can be cited.
How should it be checked?
Check the VIN against nhtsa.gov before anything else. This is an open safety recall, the remedy is a free pump replacement, and it is one of the few faults on this site with a fix that costs the owner nothing.
How can you check it yourself?
None mechanical. Enter the VIN at nhtsa.gov/recalls and read whether this campaign is listed as open. A seller saying the recall “was done” is not the same as the VIN saying so.
The question to ask the shop
Has the fuel pump recall been completed on this VIN, and is there a dealer record of it? An open campaign is free to fix but it has to actually be booked.