Beretta V6-173 2.8L (1989)
The ECM uses the P/N signal as one of the inputs to control:
^
Idle Air Control
^
VSS Diagnostics
^
EGR
TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.
1.
Checks for a closed switch to ground in park position. Different makes of "Scan" tools will read P/N differently. Refer to operators manual for
type of display used for a specific tool.
2.
Checks for an open switch in drive range.
3.
Be sure "Scan" indicates drive, even while wiggling shifter to test for an intermittent or mis-adjusted switch in drive range.
DIAGNOSTIC AIDS:
^
If CKT 434 indicates P/N (grounded), while in drive range, the EGR would be inoperative, resulting in possible detonation.
^
If CKT 434 always indicates drive (open), a drop in the idle may exist when the gear selector is moved into drive range.
