P1420 Buick Intake Air Low Pressure Switch Circuit Low Voltage

P1421 Buick Cold Start Control

Possible causes
– Lack of intake air volume (block air filter)
– Fuel injection system (Clogged fuel injector or bad fuel pump)
– Faulty Engine Control Module (ECM)
What about the obd code?
The P1421 Buick code is detected when The Engine Control Module (ECM) does not control ignition timing and engine idle speed properly when engine is started with pre-warming up condition.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P1421 Buick Description

The Engine Control Module (ECM) controls ignition timing and engine idle speed when engine is started with pre-warming up condition. This control promotes the activation of three way catalyst by heating the catalyst and reduces emissions.

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