The Army yesterday said the Pershing II missile test last Friday was not a complete success as initially claimed.

The controversial missile's complex warhead failed to maneuver properly and "did not achieve the desired accuracy," an Army spokesman said yesterday.

The Pentagon said the problem was discovered over the weekend as technicians reviewed data from the test, held at the White Sands Missile Range in New Mexico.

On Friday, Army officials had announced the missile, the key to NATO's nuclear modernization plan but which failed its first two flight tests, had a "good flight all the way," and the warhead had "landed within the target area."

But yesterday, an Army spokesman said that a loss of hydraulic pressure prevented the control surfaces of the warhead from working. Without these wing-like flaps, the warhead could not change direction on orders from its sophisticated, electronic, terminal guidance system.

As a result, it did not land near the target.

The spokesman, however, stressed that the primary objective of the Friday test was successful--seeing that the rebuilt, two-stage engines of the Pershing II worked during a test shot that was 200 miles almost straight up and 66 miles downrange. The engines had misfired, causing the destruction of the initial Pershing II test missile 17 seconds after ignition last July.

Another Pershing shot at White Sands is scheduled for next month, and two more are planned for January at Cape Canaveral, Fla., at the missile's full range of 1,000 miles.

Friday's launch was part of a speeded-up test schedule for the missile, which could be fired from bases in western Europe and hit targets inside the Soviet Union. Under a program adopted in December, 1979, the first of a planned 108 Pershing II missiles are to be ready for deployment in West Germany by December, 1983.

To meet that deadline, however, the Army has been forced to begin production of Pershing II components while still testing to see whether the weapon works.