P1779 Buick Transmission Control Indicator Lamp Circuit Malfunction

P1780 Buick Park/Neutral Position Switch Malfunction

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 Buick 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.

Buick Vehicle:Buick Regal – ?Buick Riviera – ?Buick LaCrosse – ?David Dunbar Buick – Buick Century – Buick LaCrosse – Buick LeSabre – Buick Lucerne – Buick Park Avenue – Buick Regal – Buick Verano – Buick Enclave – Buick Encore – Buick Rainier – Buick Rendezvous – Buick Terraza – Buick Riviera