Engine Control System

P1780 - Park/Neutral Position Switch Malfunction (Only For A/T)

CIRCUIT DESCRIPTION

DTC Detection Condition:

The park/neutral position switch comes on when the shift lever is in the N or P shift position. When it comes on, terminal NSW of the ECM is grounded to the 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 terminal NSW becomes 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.

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

HINT: Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.