P1393 FORD - Glow Plug Circuit Low Input Bank 2
- Faulty glow plug relay
- Faulty glow plug shunt
- Faulty glow plugs
- Glow plugs harness is open or shorted
- Glow plugs circuit poor electrical connection
- Faulty Powertrain Control Module (PCM)
California trucks it has a GPCM (Glow Plug Control Module) instead of a GPR (Glow Plug Relay).
- Engine Light ON (or Service Engine Soon Warning Light)
P1393 Ford Description
The glow plug system is monitored when the glow plugs are commanded on for more than 35 seconds and battery voltage is between 11.5-14 volts.