Note On Intermittents

Manipulate circuits No. 1230 and 1231. Look for EMI sources, such as sensor wires running along spark plug cables or high power transmitters in vicinity.

Fig 1: Code P056 Schematic (4.6L)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P056 Flow Chart (4.6L)

Courtesy of GENERAL MOTORS CORP.