Cylinder 8 glow plug failed internally or shorted to ground; Damaged, chafed or corroded wiring on the cylinder 8 glow plug circuit shorting to ground; Corroded, loose or water-contaminated connector or terminal at the glow plug or control module; Poor power or earth supply to the glow plug module or control unit (weak battery, bad earth, blown fuse or relay); Faulty glow plug control module or driver output for cylinder 8; Damaged glow plug feed from earlier repair work, such as a trapped or pinched wire.

P068E

Cylinder 8 Glow Plug Control Circuit Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
8E: FaultThe specific fault in that area

What it means

P068E means the engine or glow plug control unit has detected a low voltage or current fault in the control circuit for the cylinder 8 glow plug. The unit commands the glow plug on and sees a signal lower than expected, which points to a short to ground, excessive resistance or a failed driver. How the circuit is arranged (individual driver outputs or a separate glow plug module) depends on the vehicle and engine.

Symptoms

Engine warning light or glow plug (coil) warning light on
Hard starting or extended cranking in cold weather
White smoke and rough running on a cold start
Misfire or uneven idle until the engine warms up
Slightly higher emissions or fuel consumption when cold
Other glow plug fault codes stored alongside it

Possible causes

Cylinder 8 glow plug failed internally or shorted to groundlikely
Damaged, chafed or corroded wiring on the cylinder 8 glow plug circuit shorting to groundlikely
Corroded, loose or water-contaminated connector or terminal at the glow plug or control modulepossible
Poor power or earth supply to the glow plug module or control unit (weak battery, bad earth, blown fuse or relay)possible
Faulty glow plug control module or driver output for cylinder 8possible
Damaged glow plug feed from earlier repair work, such as a trapped or pinched wirerare

How to diagnose

Read all stored codes and freeze frame data, noting engine temperature, battery voltage and whether other glow plug codes are present.
Check battery condition and charging voltage, as low supply voltage can cause false circuit faults.
Inspect the cylinder 8 glow plug wiring, connector and terminal for chafing, heat damage, corrosion or moisture.
Check the relevant fuses, relays and earth connections for the glow plug system, following the model-specific wiring diagram.
Measure the resistance of the cylinder 8 glow plug against the manufacturer's specification and compare it with the other plugs.
Check the wiring between the control module and glow plug for a short to ground or low resistance, with the connectors disconnected.
Use a scan tool that supports it to command the glow plugs on and watch the current or status data for cylinder 8.
If the wiring and plug are good, test the module supply and earth, then confirm the driver fault before replacing the module.

How to fix

Replace the faulty cylinder 8 glow plug, and consider replacing the set if they are old, following the manufacturer's procedure.
Repair or replace damaged wiring and secure it clear of hot or moving parts.
Clean or replace corroded connectors and terminals and ensure they are fully seated and sealed.
Restore proper power and earth supply, including replacing a faulty fuse or relay once the cause of failure is found.
Replace the glow plug control module only when testing confirms a faulty output, and carry out any required coding or adaptation for the model.

Can I keep driving?

Medium severity

The car can usually be driven, but cold starting may be poor and the engine may run roughly until warm. Get it repaired soon, especially before cold weather, and stop if the engine runs badly or other warning lights appear.

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