Pontiac Repair: P420, 2002 pontiac sunfire, pontiac sunfire

Question
it's a 2002 Pontiac sunfire with a engine code of P1420 Intake Air Low Pressure Switch Circuit Low Voltage. Is it the switch that needs to be replaced and if so where do I find it? or am I looking for the cause of the low voltage. I just replaced the plugs & wires, both Coils, Air Filter and the downstream O2 sensor.

Answer
Hi Walter:

the IAT sensor is loated in the ruber snokel between the air filetr and the engine. A Low volatge code would either indicate a shorted out sensor or the signal refrence volatge wire shorted to ground (the engine or the body) follow the harness along and see if the wires are hanging out of the conduit or taped of prtions of the harness and rubbing on the engine or body anywhere. If not it may just be a bad sensor. With out the aid of a scan tool your just going to have to guess with a scan tool you could actaully read the sensor data.