Acura NSX 1991 Manual page 242

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Neutral Switch Signal (M/T)
This signals the ECM when the transmission is in neutral.
Inspection of neutral switch signal.
Check for an open in the circuit:
1. Turn the ignition switch ON (II).
2. Measure voltage between ECM
connector terminals B4 and
A26.
Is there voltage?
Check for a short in the circuit:
1. Shift transmission into gear.
2. Measure voltage between ECM
connector terminals B4 and
A26.
Is there approx. 5 V?
Neutral switch signal is OK.
Table of Contents
Check for an open in the wire:
1. Turn the ignition switch OFF.
2. Disconnect the 3P connector
from the neutral switch.
3. Connect neutral switch con-
nector terminals No. 1 to No. 3.
4. Turn the ignition switch ON (II).
5. Measure voltage between ECM
connector terminals B4 and
A26.
Is there voltage?
Repair open in the wire
between the ECM (B4) and
the neutral switch.
Repair open in BLK wire
between the neutral switch
and G101 (located at right mid-
dle of engine).
Check for a short in the wire:
1. Turn the ignition switch OFF.
2. Disconnect the ECM connec-
tor B (16P) from the ECM.
3. Disconnect the 3P connector
from the neutral switch.
4. Check for continuity between
ECM connector terminal B4
and body ground.
Is there continuity?
Replace neutral switch (see
section 13).
Substitute a known-good ECM
and recheck. If prescribed volt-
age is now available, replace
the original ECM.
ECM CONNECTORS
WIRE SIDE OF FEMALE TERMINALS
NEUTRAL SWITCH 3P CONNECTOR
WIRE SIDE OF FEMALE TERMINALS
Replace the neutral switch (see
section 13).
Repair short in the wire between
the ECM (B4) and the neutral
switch.