What happened?
In late 2020, Toyota Industries applied to the U.S. Environmental Protection Agency (EPA) for annual certification of engines installed in forklifts and other industrial vehicles. After applying, it received questions from the EPA about the application data. As the investigation widened, the company found conduct in Japanese emissions certification that included using estimated rather than measured emissions values, changing engine control unit (ECU) software to make required test conditions hold, and replacing parts during durability testing.
Toyota Industries disclosed the possible violations of Japanese regulations on March 17, 2023 and established a Special Investigation Committee. The investigation later expanded to output testing of automotive engines, where fuel injection quantities had also been changed during measurements. The official English edition of the committee’s published report, dated January 29, 2024, runs 240 pages.
Background overview: Toyota Industries (Wikipedia)
Eight passages that stood out
Beyond the high-level description of misconduct, the report records emails, file names, testing workarounds, and statements from managers and staff. Those details show how the conduct actually unfolded in day-to-day work. The eight notes below are tied back to the original pages.
A manager emailed that following the rules would miss the launch date. His superior did not reply
In April 2013, amid problems during 1KD engine durability testing, a group manager judged that there was too little time for a rerun and emailed the Assistant General Manager at the Engineering Office. He explained that following the regulations would make it impossible to submit the report by the end of May, delaying certification and affecting the production launch date. The email listed alternatives such as substituting measurements and predicting values from prior data, and asked how to proceed.
The Assistant General Manager did not reply. The committee’s forensic review also found no response.
The Assistant General Manager later told the committee that he understood keeping the launch date would require some action contrary to regulations, but hesitated to explicitly instruct the group manager by email to keep the launch date. He therefore did not respond.
Email reproduced in the report
April 25, 2013 · Group Manager to Assistant General Manager · Site translation from the Japanese-language report (◆ indicates illegible characters in the published source)
If we follow the regulations, we cannot submit the DF report by the end of May. Certification will be delayed, and that will certainly affect the mass-production start date (LO). […] If the LO deadline is to be met, […] the only options are the measures below, though I do not think they would pass SEA. ◆ Evaluate gases using direct-continuous measurements from Bench 203 and use PEMS values for PM. ◆ Substitute all emission values from Bench 205. The cross-check showed differences, so using those values to finalize the DF would be risky. ◆ Predict the 05W DF values from DF1 and past experience and submit the report. Verify them after Bench 203 is repaired. I cannot decide on these alternatives on my own, so […] I would like to consult you about what to do.
Three days after the report was filed, an email ended with a warning to take sufficient care in handling the data
With no reply from his superior, the group manager calculated deterioration factors using estimated particulate matter (PM) values. The deterioration-factor report was reviewed by the Assistant General Manager and submitted to the EPA on June 4, 2013.
Three days later, the group manager emailed staff to say the values had been finalized and the report submitted.
The email reproduced in the report closes by telling recipients to take sufficient care in handling the data.
The altered files were named with wording equivalent to “_dry/wet bulb adjustment” and stored beside the originals
In another engine case, original and altered test data were stored side by side in the same folder for each measurement time.
The altered files added wording equivalent to “_dry/wet bulb adjustment” to the original file names.
The shared folder was accessible to technical-department employees and had no password. The committee described the names as ones that could, at a glance, raise suspicion that test data had been altered, and concluded that the employee did not appear to believe the alteration needed to be deliberately hidden from colleagues or supervisors.
The engine used through 500 hours was not the same engine used from 750 hours onward
For the 2007 4Y engine durability test, emissions measurements from 750 hours onward used a different engine from the one used through 500 hours.
The report says this is clear from the different individual engine numbers recorded on the test planning documents. The staff member involved said he did not understand the durability-test regulations and did not recognize the practice as a regulatory violation.
For emissions measurement, only the catalyst was moved onto a different engine
In the same 2007 4Y testing, staff removed only the catalyst from the durability engine, installed it on a different engine, and measured emissions there.
The employee responsible explained that he believed most deterioration affecting emissions occurred in the catalyst, while deterioration of the other engine components had little effect. On that reasoning, he thought aging the catalyst and measuring it on another engine was sufficient for the deterioration evaluation.
Why the issue did not go higher: management would just say, in effect, “make it work”
The report notes that a number of problems had been reported to or discussed with the Assistant General Manager, but none were found to have been escalated to his superior, the General Manager of the Engineering Department.
The Assistant General Manager described an atmosphere in which taking a problem upward would simply result in being told, in effect, to “make it work,” and said he had partly given up on escalation as futile.
He also said he did not ask Toyota Material Handling Company (TMHC) to postpone the production launch because he believed the General Manager of the Engine Division would not help.
The committee criticized both the Assistant General Manager’s failure to escalate issues and the Engineering Department’s General Manager and Deputy General Managers for failing to pick up problems from the development floor in a timely way.
They first measured the engine normally, then used the result to decide where to increase or decrease fuel injection
In in-house output testing of the 1GD and 2GD automotive engines, fuel injection quantities were changed so the measured maximum output would reliably exceed the target and the torque curve would not look irregular.
Staff first measured output using the production ECU software without changing the fuel injection quantity, then used that result to decide where and by how much fuel injection should be increased or decreased.
They then changed ECU parameters or adjusted injection directly during testing with a device referred to as a “calibration tool.”
Investigation committee finding
The committee's account of concerns about an irregular torque curve · Site translation from the Japanese-language report
If these upward or downward variations in the measured values accumulate across engine-speed ranges, the torque curve becomes distorted. The calibration group engineers were concerned that submitting such a distorted curve as the result of an in-house output test would raise questions about the engine's performance and other matters at meetings with Toyota Motor Corporation.
Some staff initially felt uncomfortable. Then they were told, “this is how it has always been done”
Employees involved in changing fuel injection quantities during automotive-engine output testing told the committee that some of them initially felt uncomfortable with the practice.
But after supervisors or senior colleagues said, in substance, “this is how it has always been done,” they eventually began making the adjustments themselves.
What the report says about the background
The committee analyzed broader causes including weaknesses in the quality management system, a fragile quality-assurance function, the long absence of a dedicated regulatory-certification organization, and a culture that made development-schedule problems difficult to escalate.
The passages above preserve a more concrete layer of the report: an email about the collision between regulations and schedule, a superior who did not reply, altered files left openly in a shared folder, engines swapped during testing, and inherited practices passed down by senior colleagues. From Reports presents those scenes separately from the committee’s own findings and keeps each one traceable to the source pages.
Corrections to this article
All eight note references were corrected or extended to include their supporting passages in the official English edition. Late 2020 dates the EPA application, followed by the inquiry (p.5). Notes 01, 02 and 06 now use the official managerial titles; note 04 distinguishes employee testimony about legal awareness. Note 07 limits the detailed adjustment procedure to the 1GD and 2GD engines (pp.170–172).