Not in the way the headline suggests. Japan’s 2024 inquiry into five automakers covered several types of vehicle-approval tests; the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) did not describe those findings as diesel-emissions-test cheating. A separate Toyota Industries case concerned horsepower-output certification for diesel engines. A different, Hino-related inquiry did involve emissions testing.
What did Japan’s 2024 automaker inquiry find?
On June 3, 2024, MLIT said it had directed 85 vehicle and equipment manufacturers holding type designations to investigate their type-approval applications. In its initial summary, four companies—Mazda, Yamaha Motor, Honda and Suzuki—had completed investigations and reported misconduct; Toyota had also reported misconduct while its investigation was still underway. The problems involved different tests and records, not one shared diesel-emissions scheme. MLIT’s June 3 summary lists the reported categories.
- Toyota: pedestrian-protection test data and modifications to vehicles used in crash tests.
- Mazda: engine-control software rewriting during output tests and modifications to crash-test vehicles.
- Yamaha Motor: noise-test conditions and horn-test records.
- Honda: noise-test records.
- Suzuki: braking-test records.
Those categories matter: a type-approval investigation can involve many tests of whether a vehicle meets required standards. The ministry’s summary did not identify these five companies’ reported issues as diesel-emissions testing.
How did the 2024 inquiry conclude?
MLIT’s chronology records that it announced inspection results for four companies on June 28, Toyota submitted its final investigation report on July 5, and the ministry reported its Toyota inspection findings on July 31. That inspection recognized misconduct in 14 Toyota models: seven that Toyota had reported and seven additional models. On August 9, the last company still completing its investigation reported no misconduct. The final tally was five companies reporting misconduct out of 85 investigated; 80 reported none. MLIT’s chronology, current as of August 26, 2024, gives the sequence and totals.
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- Premium Cast Iron: The diesel injector tester forged by high-quality cast iron, its durability and rigidity is dramatically increased. It also consists of a plastic fuel cup to contain the fuel, and with a stainless pressure gauge to detect air pressure precisely.
- Large Measuring Range: With precision dual scale gauge, the measuring value range from 0-600 bar/ 0-8000 psi, Max test pressure up to 60M Pa. (100 mm Dial, 3/8" BSP thread.) The transparent fuel measuring cup can hold 0.8L oil, and with the filter to help conduct kinds of injector nozzles tests.
- Superior Tests Ability: The tool set is capable of accomplishing proper injection nozzle opening pressure test, leakage test, chattering test, an inspection of spray pattern, and Atomization. With such a multifunctional test capability, the diesel injector tester is the ideal tool for the examination of auto diesel injectors.
- Standard Accessories: The injector pop tester kit is equipped with 60MPa pressure gauge, handle, high-pressure pipes, A and B type with m.m. size nuts (12 X 1.5) and (14 X 1.5) for connections, 0.8L fuel cup with a 5-micron original Bosch filter, piston/element, and delivery valve. Two extra oil pipes are included in the package for your testing use.
- Wide Utility: Diesel fuel injector tester is widely used in the calibration of fuel injectors of diesel engines of automobiles and tractors. It is suitable for all types of diesel injectors except (CRDI) Common Rail Diesel Injectors.
What was the Toyota Industries diesel-engine case?
Announced on January 29, 2024, this was a separate certification issue. Toyota Motor Corporation said Toyota Industries had reported irregularities in horsepower-output certification testing for three diesel engine models it had been commissioned to develop. The engines were tested with electronic control units (ECUs) using software different from the mass-production software, producing smoother output results with less variation. This was an engine-output certification test, not an emissions test. Toyota’s January 29 statement describes the reported conduct and its response.
Toyota said the engines were used in ten vehicle models worldwide, six of them in Japan. It said its re-verification confirmed that the affected engines and vehicles met engine performance output standards, and that stopping their use was not necessary. Toyota also said Toyota Industries and Toyota temporarily suspended shipments of the affected engines and vehicles and would explain the matter to authorities. These are Toyota’s statements about its findings and the response at that time; they do not establish current model-by-model status or later owner remedies.
Rank #2
- Superior Tests Ability: Diesel compression tester stands 17 inches tall; consists of a plastic fuel cup to contain the fuel, and with a stainless pressure gauge to detect air pressure precisely,the diesel injector tester forged by high-quality cast iron, its durability and rigidity is dramatically increased
- Large Measuring Range: Dial reading 0-600 bar or 0-8000lbs,Fuel tank capacity: 0.75L.Biggest test pressure: 60MPa;Plunger Hole: 0.39/10mm;Nozzle Connector: M12 / M12 (filaments) / M14
- Fit For: S60H for 6190/6200/6170 Diesel /CR-C test injectors: for bos-ch, for Den-so, and for Del-phi common rail injectors
- Common Rail Injecto Simple Operation: With the conventional nozzle tester,It can meet the needs of detecting common rail injectors and effectively redu ce the cost of maintenance equipment. The diesel injector nozzle tester need to be purchased separately. The fuel injector tester kit can be used for the detection of atomization effect, pre-injection, discharge point, emission and full load point.
- Wide Application: The common rail injector tester adopts imported PWM control chip, which; This fuel injector tester is the special equipment for inspecting fuel injectors. It can verify various mechanical tests of fuel injectors, such as opening pressure test, leakage test, atomization, and chattering test. With diversity function, and simple operation
Which separate case actually involved emissions testing?
A separate inquiry followed Hino’s emissions and fuel-economy testing misconduct. In a July 12, 2022 report, MLIT said Scania Japan had reported irregularities in emissions deterioration-factor endurance tests for four engine types. At mileage points requiring at least two emissions measurements, Scania Japan had measured once. For two types, it conducted the initial test at 6,100 km rather than within the specified 5,000 km plus or minus 500 km range. MLIT’s report listed 1,155 domestic vehicles equipped with the engines. MLIT’s July 2022 report concerns this distinct Hino-related review, not the 2024 five-automaker inquiry.
How the cases differ
| Case | Company or scope | Test issue | What the cited source establishes |
|---|---|---|---|
| 2024 type-approval inquiry | Mazda, Yamaha Motor, Honda, Suzuki and Toyota; 85 companies were directed to investigate | Varied tests and records, including crash, output, noise, horn and braking matters; the June summary did not identify diesel-emissions testing | MLIT’s final tally was five companies reporting misconduct; its Toyota inspection recognized misconduct in 14 models |
| 2024 Toyota Industries case | Three diesel engine models; Toyota said these were used in ten vehicle models worldwide, including six in Japan | Horsepower-output certification using ECU software different from production software | Toyota reported the irregularity and described its re-verification and temporary shipment suspension |
| 2022 Hino-related review | Scania Japan reported findings for four engine types; MLIT listed 1,155 domestic vehicles | Emissions deterioration-factor endurance measurements and test mileage | MLIT reported the findings in the separate inquiry prompted by Hino’s testing misconduct |
What is known about current vehicle status?
The cited MLIT chronology runs through August 2024, while Toyota’s account of the Toyota Industries response is dated January 2024. Those sources do not establish comprehensive legal or registration status for each model, whether every affected vehicle is currently shipping, or what owner remedies may have followed through October 8, 2026. A buyer or owner seeking a decision about a specific vehicle should check current notices from the relevant manufacturer and Japanese authorities rather than infer an individual vehicle’s status from these investigation summaries.
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Best Value
- Large Measuring Range: Dial reading 0-600 bar or 0-8000lbs,Fuel tank capacity: 1.5L.Biggest test pressure: 60MPa; Plunger Hole: 0.39/10mm; Nozzle Connector: M12 / M12 (filaments) / M14
- Simple To Use: Fill the 1500mL oil cup and press the lever to eliminate air from the tester; Connect your oil tube then press lever again; Connect injector nozzle with tube and start testing; Be sure to flush the tester before your first use
- Superior Tests Ability: Diesel compression tester stands 17 inches tall; consists of a plastic fuel cup to contain the fuel, and with a stainless pressure gauge to detect air pressure precisely,the diesel injector tester forged by high-quality cast iron, its durability and rigidity is dramatically increased
- Wide Utility: This injector pop tester kit was designed to check for leakage, spray pattern and chatter characteristics in your diesel engine; Ensure optimal operation in your vehicles and farming equipment,it is troubleshoot for mechanical issues after rebuilding and servicing
- Premium Cast Aluminium: Diesel Injector Nozzle Tester in die casting aluminium alloy body, with carefully machined internal dimensions, Injection pump with hand lever
Rank #4
- With precision dual scale gauge, the measuring value range from 0-600 bar/ 0-8000 psi, Max test pressure up to 60M Pa. (100 mm Dial, 3/8" BSP thread.) The transparent fuel measuring cup can hold 0.8L oil, and with the filter to help conduct kinds of injector nozzles tests.
- Our diesel injector tester is capable of accomplishing proper injection nozzle opening pressure test, leakage test, chattering test, an inspection of spray pattern, and Atomization. With such a multifunctional test capability, the diesel injector tester is the ideal tool for the examination of auto diesel injectors.
- The injector pop tester kit is equipped with 60MPa pressure gauge, handle, high-pressure pipes, A and B type with m.m. size nuts (12 X 1.5) and (14 X 1.5) for connections, 0.8L fuel cup with a 5-micron original Bosch filter, piston/element, and delivery valve. Two extra oil pipes are included in the package for your testing use.
- Large engine compression tester features a solid 4.5 x 3.5-inch mountable base, a 4-inch dual scale gauge, and a rotating handle; Kit also includes an attachable 15.5-inch long lever with 4.5-inch rubber grip, a 6.5 x 4.5-inch semi-clear fuel container, and 3 high-pressure nozzles
- Brass Bourdon tube Pressure gauge - 100 mm Dial, 3/8 " BSP thread Dual Scale Gauge Range:0 - 60 Mpa & 0 - 8000 PSI (See image 2 Above) High pressure pipes 'A' and 'B' type with m.m. size nuts (12 X 1.5) and (14 X 1.5) for connections
Rank #3
- Large Measuring Range: Dial reading 0-600 bar or 0-8000lbs,Fuel tank capacity: 0.75L.Biggest test pressure: 60MPa;Plunger Hole: 0.39''/10mm;Nozzle Connector: M12 / M12 (filaments) / M14
- Simple To Use: Fill the 750mL oil cup and press the lever to eliminate air from the tester; Connect your oil tube then press lever again; Connect injector nozzle with tube and start testing; Be sure to flush the tester before your first use
- Superior Tests Ability: Diesel compression tester stands 17 inches tall; consists of a plastic fuel cup to contain the fuel, and with a stainless pressure gauge to detect air pressure precisely,the diesel injector tester forged by high-quality cast iron, its durability and rigidity is dramatically increased
- Wide Utility: This Diesel Fuel Pressure Tester Kit was designed to check for leakage, spray pattern and chatter characteristics in your diesel engine; Ensure optimal operation in your vehicles and farming equipment,it is troubleshoot for mechanical issues after rebuilding and servicing
- Premium Cast Iron: Diesel Injector Nozzle Tester in die casting aluminium alloy body, with carefully machined internal dimensions, Injection pump with hand lever
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