Possible causes

– Faulty Park/Neutral Position (PNP) switch
– Park/Neutral Position (PNP) switch harness is open or shorted
– Park/Neutral Position (PNP) switch circuit poor electrical connection
– Misadjusted Park/Neutral Position (PNP) switch

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1780 LEXUS Description

The Park/Neutral Position (PNP) switch detects the shift lever position and sends signals to the ECM. The ECM receives signals (NSW, R, 2 and L) from the park/neutral position switch. When the signal is not sent to the ECM from the park/neutral position switch, the ECM judges that the shift lever is in D position.