Notes On Intermittents

Check for gear selector switch and shift indicator out of adjustment. Check for intermittent open or short to ground in circuit No. 434 between ECM and switch.

NOTE: The following step numbers refer to circled numbers on diagnostic chart. See Fig 1 . For circuit identification, see Fig 2 .

Status "HI" at all times means that circuit No. 434 12-volt supply from ECM pin "A2" is never being shorted to ground in Park or Neutral.
Status "LO" at all times means that circuit No. 434 12-volt supply from ECM pin "A2" is shorted to ground in all gear selector ranges.

Fig 1: Identifying ECM Input EI74: PARK/NEUTRAL Circuit Flow Chart

Courtesy of GENERAL MOTORS CORP.

Fig 2: Identifying ECM Input EI74: PARK/NEUTRAL Circuit Flow Chart Circuit

Courtesy of GENERAL MOTORS CORP.