The common rail system is something DENSO developed to achieve clean diesel. 
In the production processes for the injector that serves as its heart, five units were discovered that leaked small amounts of fuel.

Right away, the manager of the production section went to the original designer in the Production Engineering Department and requested an investigation. 
The problem was even more serious than imagined.

An emergency meeting that included the general managers of the Manufacturing Department and the Quality Assurance Department was immediately convened.
Regular production was halted. The injectors in stock were also segregated.

DENSO wanted to notify the recipient of the matter as quickly as possible, but what caused the shape of the screw to be defective? 
To what extent were actual products affected? 
Were there more than the defective items that had been found? 
Nothing was clear. 
To keep from stopping the customer's production line, DENSO was unable to report the matter without due care. 
DENSO wanted to gather accurate information.

DENSO also visited the supplier and continued investigating the production history and conducting recurrence testing. 
As a result of this, it was determined that a small nick in a blade resulted in a fault when the screw was machined. 
Meanwhile, identification of the defective lots was not going well. 
Awareness of traceability was still low at that time, and so system for retracing had been established.

After repeated investigation and testing, the tired-looking person carrying this out began hold the tempting home that the defect might not actually cause a problem, but in the end the parts were found to be unacceptable. 
The report to the customer was made about three days after the first defective part had been discovered.

Already, over a thousand completed vehicles bound for overseas destinations had been loaded onto ships that had departed. 
The worst-case scenario of the defective vehicles entering the market could be averted, but the injectors on over a hundred vehicles had to be replaced at overseas ports.

Instead of keeping the matter in-house, DENSO immediately shares all risks the customer might face, and works together with them to resolve the matter.
Is the action about to be taken truly in keeping with the perspective of the customer and the end user? 
This is what we continue to ask ourselves.