Volkswagen is still struggling with “massive” software problems with its ID3 compact electric car, according to a German business magazine.

The software glitches may force it to abandon the EV’s planned sales launch in Europe this summer, Manager Magazin reported. 

The problems stem from the basic architecture of the ID3’s software, which was developed “too hastily,” the magazine said, citing VW’s own experts. Many of the system’s elements do not understand each other, leading to dropouts and other difficulties, the report said.

Hundreds of test drivers of the car are reporting up to 300 errors a day, the magazine said.

More than 10,000 technicians are trying to solve the problems, which could delay the ID3’s launch by up to a year, the report said.

The ID3 will be a rival to the Tesla Model 3 and base models will cost less than 30,000 euros in Germany. It is the first electric car based on the automaker’s MEB electric architecture developed to offer a long driving range and fast charging. VW said the platform will underpin 27 EVs by the end of 2022 from its VW, Audi, Skoda and Seat brands including the VW ID4 crossover aimed at customers in the U.S. and China.

The Golf-sized ID3 is targeted at European market and is not expected to be sold in the U.S.

VW Group is touting the ID3 as a car that is as strategically important to the automaker’s future as the Beetle and the Golf were in the past. CEO Herbert Diess says the ID3 will move “electric mobility from niche to mainstream.”

In January, VW said that establishing the car’s powerful new electronics and software architecture was a challenge but said that the market launch in the summer remained in place.

Manager Magazin reported in December that the glitches meant over 20,000 ID3 cars would be built without a full software suite, requiring teams of engineers to manually fix the problem post-production at additional cost.

VW started series production of the ID3 at its plant in Zwickau, Germany, in November. It said it is using the months until deliveries of the first cars to fix issues that may come up during further field testing.

Any delay in the ID3 could prove costly for VW, which is counting on the model to help meet stringent new European fleet emissions targets introduced at the beginning of last month.