Possible causes

– Idle Air Control Valve harness is open or shorted
– Idle Air Control Valve circuit poor electrical connection
– Faulty Idle Air Control Valve

Symptoms

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

P1508 Information for specific makes

P1508 ACURA
P1508 BUICK
P1508 CADILLAC
P1508 CHEVROLET
P1508 DODGE
P1508 GMC
P1508 HONDA
P1508 HYUNDAI