Credov

P0674 fault code: what it means

P0674: SkyActiv-D: glow plug No.4 circuit fault. Hard cold starts and smoke; glow plug is the usual fix.

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

  1. glow plug No.4
  2. glow plug connector or wiring
  3. glow control module

P0674 by make

Mazda

SkyActiv-D: glow plug No.4 circuit fault. Hard cold starts and smoke; glow plug is the usual fix.

Usual causes: glow plug No.4; glow plug connector or wiring; glow control module

Mercedes-Benz

Glow plug circuit fault, cylinder 4. Glow plugs on Mercedes diesels can seize and snap on removal, adding labour.

Usual causes: failed glow plug; wiring or connector fault; glow plug control module

Not sure what P0674 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.