Honda Acura NSX 1991 Service Manual page 254

Idle Control System
This signals the PGM-FI ECU when the transmission is in Neutral.
inspection of M/T neutral Switch
Signal
Turn the ignition switch ON.
Measure voltage between 87 I+)
terminal and A26 (-1 terminal in
Neutral position.
I
Is there voltage?
I
I
NO
Is there approx. 10 V?
Y E S
signal is OK.
I I - 7 8
0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 ~
I
A26 I-)
Disconnect the 3P connector on
Connect LT GRN terminal to BLK
terminal.
Is there voltage?
Disconnect "B" connector from
engine wire harness only, not the
ECU.
Replace M/T neutral switch.
0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0
Substitute a known-
g o o d E C U a n d r e -
check.
if prescribed voltage is
now avaiiebie, replace
the original ECU.
Repalr short in LT GRN
w i r e b e t w e e n E C U
neutral switch.