P0674 Code Causes?

[l1nuxxx]

Hi guys,

Been getting a reaccuring fault code coming up P0674 Glow Plug 4 Circuit Failure over the last few weeks. Changed the plugs to no effect. It isn't always Glow Plug 4 either, sometimes it's Plug 2 or 3 Curcuit Failure. Car takes a bit longer to start in the cold as well.

Could it be knackered pre-heater plugs?

Cars a TDi 150

Thanks

 

[Allan_84]

this is what you get from rosstech wiki, you may look in the special notes, theres a guide..
P0674 - Cylinder 4 Glow Plug Circuit (Q13): Electrical Fault

 

[towcester vag]

had same with mine
checked glow plugs and they worked every time using voltmeter/ammeter/continuity
checked operation of relay by pollen filter ok
replaced loom from glow plugs to terminal block in plastic trunking behind battery (cured)
couldnt fault wiring loom in anyway

 

[l1nuxxx]

Thanks guys,

At leat that gives me a place to start and it doesn't look too bad a fault.

 

[tarmacterrorist]

Hi

I have had a previous fault which was 2 seperate glow plugs (intermittent), I cleared this some time ago with VCDS and the light has just come back on. Its now registering a P0674 same as above.

I guess Im going to have to buy a multimeter and trace the fault. I originally thought it may have just been the glow plugs themselves since my car is quite high mileage and there is no record of them being changed although I want to get to the bottom of the problem straight away.

In most peoples experience does it end up being the harness rather than the plugs themselves? And if I am to change the harness do you think I should change the plugs as a matter of course??