Engine Control System

DTC P1780 - PARK/NEUTRAL POSITION SWITCH MALFUNCTION(ONLY FOR A/T)
CIRCUIT DESCRIPTION

DTC Detection Condition:

The park/neutral position switch goes on when the shift lever is in the N or P shift position. When it goes on terminal NSW of the ECM is grounded to body ground via the starter relay, 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 becomes battery positive 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.

HINT: After confirming DTC P1780, use the TOYOTA hand-held tester to confirm the PNP switch signal from the CURRENT DATA.

Wiring Diagram:

Step 1:

Step 2:

INSPECTION PROCEDURE