Al Jazeera's John Terrett, reporting from Washington, said that the grand jury's decsions could lead eventually to criminal charges against Toyota.

"This subpoena relates to three of the things that have dogged the company in the past couple of years; the driver's side mat that apparently rucked up and got stuck under the accelerator pedal, the sticking accelerator pedal itself, and the braking problem on the popular hybrid the Prius," he said.

"It will take a while for all this to play out, but if the grand jury decides there is enough evidence for criminal charges to be pressed then that is what will happen." 

Documents released 

In video


Al Jazeera's John Terret reports on Toyota's mounting problems

Toyota has recalled more than 8.5 million vehicles worldwide in recent months following a series of complaints and a slew of lawsuits linking vehicle flaws to 30 deaths across the US.

Documents released in the US on Sunday ahead of the congressional hearings have shown that Toyota knew of safety problems with some of its vehicles as early as last June, and lobbied US regulators to head off an investigation.

Terrett said that the congressional committees were likely to "go after" Toyoda when he appears before them.

"Congressional committees are generally a chance for congress to grandstand, to have their say, and generally to appeal to their constituents back home," he said.

"They are going to do this on a big scale on Wednesday." 

One internal company memo uncovered by congressional investigators showed Toyota officials boasting of saving $100m by limiting the extent of vehicle recalls.

The documents also cite efforts to delay safety regulations, avoid investigations, and stall industry requirements.

The memos are among thousands that a congressional committee has requested in a subpoena of Dimitrios Biller, who worked as a US lawyer for Toyota from 2003 to 2007.

Biller said the internal company documents show the firm was hiding evidence of safety defects from consumers and regulators.

In a document referring to important security issues, Toyota mentioned "sudden accelerations" on some of its vehicles, showing the company was aware of such problems in July of last year.