TGE/Troubleshooting 2JZ-GE — Park Neutral Position Switch Circuit, page 83

Park Neutral Position Switch Circuit

CIRCUIT DESCRIPTION
The park/neutral position switch goes on when the shift lever is in the N or P shift position. When it goes on the terminal NSW of the ECM is grounded to body ground via the starter relay and theft deterrent ECU, thus the terminal NSW voltage becomes 0 V. When the shift lever is in the D, 2, L or R position, the park/neutral position switch goes off, so the voltage of ECM terminal NSW becomes positive battery voltage, the voltage of the ECM internal power source.
If the shift lever is moved from the N position to the D position, this signal is used for air–fuel ratio correction and for idle speed control (estimated control), etc.
When the park/neutral position switch is off, code "51" is output in the test mode diagnosis. (This is not abnormal.)

WIRING DIAGRAM

Engine Control Module
B+
76 NSW
E9

7   8 B-W   6   ST   4   B   13   B-W   B-W
W   1J        1K         J2
Ignition Switch
J/B No.1

4 1J
J/B No.1
4 1B

B-W
6
Park/Neutral
Position
Switch
5

W   B   B   3
              EA1   B
2   2   2
2
5   1
2
Starter Relay
3   2
R/B No.2

1 EA3
B
S3 1
Starter

ALT
MAIN

1 2A   2

B
Battery

L-O   6   L-O   10   L-O   25   4   W-B
      IB2         IF2         T13   T7

Theft Deterrent
and Door Lock
Control ECU

P21137