Circuit Description

WARNING: This page is about a different car, the 2003 Toyota Matrix and 2003 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.

The neutral start switch goes on when shift lever is in N or P shift position. When it goes on, terminal NSW of ECM is grounded to body ground via starter relay, thus terminal NSW voltage becomes 0 V. When shift lever is in D, 2, L or R position, park/neutral position switch goes off, so voltage of ECM. Terminal NSW becomes battery voltage and voltage of ECM internal power source. If shift lever is moved from N position to D position, this signal is used for air-fuel ratio correction and for idle speed control (estimated control), etc.

Detecting condition of DTC is when 2 or more switches are ON simultaneously for N, 2, L and R positions (2 trip detection logic) and when driving condition is under following conditions for 30 seconds or more with neutral start switch ON, N position (2 trip detection logic):

Vehicle speed is 44 mph (70 km/h) or more.
Engine speed is 1500-2500 RPM.

After confirming DTC P1780, use hand-held tester to confirm neutral start switch signal from CURRENT DATA.