Tesla has halted production of its Model 3 sedan, the second time the assembly line has stopped on the company’s new, lower-priced all-electric model.

The company told news sources that the production shutdown was planned and is temporary, and is using the interval to improve its automated assembly procedures.

According to Buzzfeed, workers will use vacation days or remain unpaid during the shutdown, which is expected to last four to five days.

Last year, Tesla founder Elon Musk originally said that the company would build 5,000 Model 3s per week by the end of 2017, and expected that would grow to 10,000 per week sometime in 2018. Issues with the assembly line, which relies heavily on robots, has created delays and resulted in only a trickle of cars leaving the factory.

More than 500,000 people put down refundable deposits on the new model, but last summer during a quarterly report, Musk reported that some 63,000 buyers had already cancelled their orders when delivery was delayed.

In a recent interview with CBS, which Musk retweeted, he said that the company needs to be better at meeting goals, and that a complex network of conveyor belts on the assembly line slowed production and “we got rid of that whole thing.”

Tesla had previously suspended Model 3 production for four days in February to adjust equipment, and the company said there could be more down time coming in the following months.

Forbes reported that, according to Tesla’s 2017 filing, it has $5.6 billion in contractual obligations due in 2018, and at the end of 2017, owed $2.39 billion in payables but with only $515 million in receivables.

Earlier this month, Tesla said that it plans to start producing the new Model Y electric SUV in November 2019 in California, and adding production in China two years later, with an ultimate goal of building 1 million of the vehicles per year. Musk also previously showed an all-electric tractor-trailer he said the company would build, along with a new roadster.