P1774 GMC Low Coast Brake Solenoid Valve Function

Possible causes

– Faulty Low Coast Brake Solenoid Valve
– Low Coast Brake Solenoid Valve harness is open or shorted
– Low Coast Brake Solenoid Valve circuit poor electrical connection

Tech description

There is a service bulletin for a various Models with the RE5R05A transmission.
Factory Service Bulletin OBDII Code P1774 GMC

Symptoms

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

P1774 GMC Description

Low coast brake solenoid valve is turned