TOKYO – Auto makers still are trying to assess the damage from Friday’s massive earthquake and tsunami off the coast of northeastern Japan.

Toyota, Honda, Nissan, Mitsubishi, Fuji Heavy Industries and Mazda suspended production at all domestic plants on Monday to take stock of damage and the impact on their supply chains.

Nissan tentatively plans to resume production at all but two of its plants (Tochigi and Iwaki) this Thursday. Toyota will make a decision about whether to resume production on Wednesday.

Honda, which has been able to contact only 73 of its 113 suppliers in the region, says it is suspending all production through March 20 at the following plants: Sayama (CR-V, Accord, U.S. Fit, Acura RL and TSX); Ogawa (engines); Tochigi (transmissions and chassis); Hamamatsu (transmissions and marine engines); and Suzuka (Civic, Civic Hybrid, Insight and Honda CR-Z).

It also is shutting down its Kumamoto motorcycle factory March 15-20. Other facilities in the Tochigi area, including Honda R&D and Honda Engineering, will be idled through March 20. The auto maker says 17 people were injured at Honda R&D as a result of the earthquake.

Honda is continuing to assess the impact on its North American operations, which use some parts from Japan.

Mitsubishi and Mazda, as well as minicar makers Suzuki and Daihatsu, are scheduled to resume production on Wednesday. Subaru-maker Fuji says its operations will be closed through this Wednesday.

Many highways linking the region to Japan’s main population centers in Tokyo, Yokohama and further south to Nagoya and Osaka are closed, while the port of Sendai, the main seaport in the northern region, is reported to have been destroyed by a 32-ft. (10-m) high tsunami and fire that followed.

News reports claim the port will be out of commission for several months.

Most of the region is without water and electricity, and the death toll is now expected to exceed 10,000.

Three reactors at the Fukushima Daichi nuclear plant have partially melted down and reportedly are leaking low levels of radiation.

Nissan confirms the damage at its Oppama and Tochigi car plants. The Tochigi plant, in Kaminokawa, makes Infiniti and other premium cars including the GT-R and Z, while the Oppama plant produces the Leaf electric car.

Nissan also says damage occurred at its Iwaki and Yokohama powertrain plants. The Iwaki plant, located 40 miles (25 km) south of the damaged Fukushima Daichi nuclear facility, builds the auto maker’s VQ V-6 engine.

In addition to supplying the auto maker’s Tochigi assembly plant, the Iwaki facility provides VQ engines to Nissan’s Kyushu plant, which builds the Murano cross/utility vehicle, and to the Hiratsuka plant of Nissan Shatai, an affiliated manufacturer located west of Nissan’s Yokohama headquarters. The plant produces the Elgrand minivan.

Were the Iwaki plant to be closed for an extended period – there is still much confusion about the nature and extent of the damage at the Fukushima nuclear plant – it would seriously impact on the auto maker’s global business, because the plant is the main source of engines for Nissan’s larger and upscale cars.

Also incurring damage were the Sawa and Fukushima plants of Hitachi Automotive Systems, Nissan’s main parts supplier. No details were provided.

Meanwhile, Kanto Auto Works and Central Motor, both affiliates of Toyota, have three plants in the region, including a new facility in Ohira, east of Sendai in Miyagi prefecture, building the new Yaris.

A Central Motor spokesman could not be reached by telephone, although an official at the auto maker’s soon-to-be-shuttered plant in Sagamihara, Kanagawa prefecture, says all of the company’s employees are safe. The official, who could not confirm whether the plant had suffered any structural damage, indicated the facility currently is without electricity, water and gas.

A spokesman for Kanto Auto Works at its headquarters in Yokosuka, Kanagawa prefecture, confirms damage to two Iwate plants 80 miles (50 km) north of Sendai but provides no details.

Combined, the three plants can produce 420,000 cars – mostly the Corolla, Corolla derivatives and Yaris. They represent 10% of Toyota’s domestic capacity.

Analysts believe Toyota, more than any other Japanese car maker, has sufficient production capacity elsewhere in Japan – an estimated 1 million units of excess capacity – to absorb this loss in a worst-case scenario. It also has huge cash reserves.

Toyota suppliers have suffered damage to their production facilities in the region, although the extent still is being assessed.

A spokeswoman for Toyoda Boshoku, the auto maker’s main interior and seating supplier, confirms structural damage to the walls and floor of its new Miyagi facility adjacent to Central Motor’s Ohira assembly plant. Extent of the damage is not known at this time.

In addition to its Ohira plant, Toyoda Boshoku produces seats for the Yaris, Aurus and Blade models at its Kitagami facility, adjacent to Kanto Auto Works’ vehicle plant, and seats, center liners and engine covers nearby at an operation in Kanegaseki.

Toyota Motor Hokkaido, located to the north in Tomakomai, makes automatic and continuously variable transmissions for such models as the Vitz, Corolla, Camry, Aurus, Sienna and IMV, along with the Lexus ES and RX series.

A spokesman says the plant suffered no major damage; nor did the port of Tomakomai, thus it should be able to resume shipments to Aichi prefecture and Kyushu, where Toyota has assembly operations. Most of the plant’s output is for Toyota and Lexus cars built in central Japan.

Toyota Motor Tohoku and Primearth EV Energy, both with plants in Kurokawa, Miyagi prefecture, could not be reached by telephone.

Toyota Motor Tohoku makes electronically controlled brake systems for Toyota and Lexus hybrids, including the Prius, Harrier (sold overseas as the RX 450h), Highlander, Camry, Estima and GS 450h.

It also produces electronic modulated suspension systems for Alphard and Ipsum minivans; active height-control devices for Land Cruiser and Lexus LX570 SUVs; torque converters for the Estima, Camry, Aurus, Corolla, ES350, Premio and Allion; and axles for the Belta, Aurus and Blade.

Toyota isn’t commenting on whether it has alternate suppliers.

Primearth’s ¥30 billion ($353 million) Miyagi plant, which opened in January, makes nickel-metal-hydride batteries for Toyota and Lexus hybrids. The Toyota subsidiary has two other plants in Kosai, Shizuoka prefecture.

Nippon Piston Ring, which has its main plant in Ichinoseki, Iwate prefecture, confirms equipment damage, although there was little damage to the plant’s structure. The facility supplies piston rings to Toyota, Nissan, Honda and Isuzu.

Sumitomo Rubber Industries, maker of Dunlop tires, reports minor damage to its Shirakawa plant in Fukushima prefecture. A spokesman, who advises information still is incomplete, believes it will be able to ship tires from the region.

Elsewhere, Honda reports its Mooka plant in Tochigi prefecture was “severely hit.” It makes engine, transmission and suspension parts for all Honda models built in Japan.