Failed cylinder 3 glow plug (open-circuit heating element); Corroded, loose or damaged glow plug connector or supply terminal at cylinder 3; Damaged, chafed or broken wiring between the glow plug control module and cylinder 3 glow plug; Fault in the glow plug control module output for cylinder 3; Blown fuse or poor power or earth supply to the glow plug control module; Fault inside the engine control unit, or a software issue where the manufacturer has documented one for that engine.

P0673

Cylinder 3 Glow Plug Circuit/Open.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
73: FaultThe specific fault in that area

What it means

P0673 is the SAE J2012 generic code for an open circuit in the cylinder 3 glow plug circuit. The glow plug control module or engine control unit monitors the current or voltage in each glow plug circuit, and it has seen no current flow, or a reading outside the expected range, for cylinder 3 when the plug was switched on. Which control unit handles this, and how many cylinders are monitored individually, depends on the engine.

Symptoms

Hard starting or extended cranking on a cold engine
White smoke on cold start and a rough idle until the engine warms up
Glow plug or engine management warning light on the dashboard
Misfire or uneven running on cylinder 3 when cold
Increased fuel consumption and emissions on cold starts
No noticeable symptoms in warm weather

Possible causes

Failed cylinder 3 glow plug (open-circuit heating element)likely
Corroded, loose or damaged glow plug connector or supply terminal at cylinder 3likely
Damaged, chafed or broken wiring between the glow plug control module and cylinder 3 glow plugpossible
Fault in the glow plug control module output for cylinder 3possible
Blown fuse or poor power or earth supply to the glow plug control modulepossible
Fault inside the engine control unit, or a software issue where the manufacturer has documented one for that enginerare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting engine temperature and battery voltage when the fault set, and check whether other glow plug cylinders are also flagged
Check the battery condition and charging voltage, as low voltage can upset glow plug diagnostics
Visually inspect the cylinder 3 glow plug connector, terminal and wiring for corrosion, heat damage, chafing or looseness
Check the relevant fuses and the power and earth supplies to the glow plug control module against the wiring diagram
With the plug disconnected, measure the cylinder 3 glow plug resistance and compare it with the specification for that engine
Check the wiring continuity from the control module connector to the glow plug, and for shorts to earth or supply
Use a bi-directional scan function, if available, to command the glow plugs and check current draw and the voltage at the plug
If the plug and wiring are good, test the control module output as directed by the manufacturer's procedure for that engine

How to fix

Replace the cylinder 3 glow plug if it is open circuit, taking care with removal because seized plugs can snap, and tighten to the specified torque
Clean or replace the corroded or damaged connector and terminal
Repair or replace the damaged wiring section between the control module and the glow plug
Replace the glow plug control module if its output for cylinder 3 is confirmed faulty
Restore the faulty fuse, power supply or earth connection, and find out why it failed
Clear the code after repair and confirm it does not return on a cold-start test

Can I keep driving?

Low severity

The car can normally be driven and booked in for repair, although cold starting may be poor and a failed plug can mean other plugs are ageing too. Avoid repeated long cranking attempts in cold weather.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.