Hello , thanks for your question in the autoaid Community.
Your described fault Code means: 1 - GLOW CIRCUIT, MALFUNCTION OR CIRCUIT GLOW PLUG CONTROL UNIT
This fault could be a faulty glow plug, wiring to the plug or the glow plug control unit.
To check this make the following:
Enclose the Glow Plug ECU and take the Plug from this, here is the Battery Plus and other control wires, but you need the Plus Pin.
After the finding of this cable (in most times is this the biggest and Red cable) you see 4 other cables, these cable goes to the glow plugs.
Now take a test light, the stripe from this must pins at the plus cable, the other side have to pin into the 4 cables.
If the lamp lights, then the glow plug and cable are okay.
If this at one cable doesn´t lights, then you have to check this cable and glow plug.
Sometimes the glow plug destroy the glow control unit, then you have to renew both..
I hope that i could help you.