Cylinder 8 glow plug ageing or degraded, with resistance out of specification; Corroded, loose or damaged connector or terminal at the glow plug; Damaged wiring to the cylinder 8 glow plug, such as chafing, high resistance or a partial short; Poor earth or power supply affecting the glow plug circuit; Fault in the glow plug control module or output stage for that channel; Outdated or faulty control unit software where the manufacturer has documented a known issue for that engine.

P06C0

Cylinder 8 Glow Plug Circuit Range/Performance.

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
C0: FaultThe specific fault in that area

What it means

P06C0 is a generic powertrain code meaning the engine control unit has found the cylinder 8 glow plug circuit working outside its expected range or performance. The control unit monitors the current draw or feedback from the glow plug output stage and compares it with what it expects for the commanded heating phase. The exact way this is monitored, and which glow plug is 'cylinder 8', depends on the engine and its firing order.

Symptoms

Engine light or glow plug warning lamp on
Hard starting on cold mornings
Rough running or misfire for the first minute after a cold start
White smoke from the exhaust when cold
Slightly higher emissions or noisy idle when cold
No noticeable symptoms when the engine is warm

Possible causes

Cylinder 8 glow plug ageing or degraded, with resistance out of specificationlikely
Corroded, loose or damaged connector or terminal at the glow pluglikely
Damaged wiring to the cylinder 8 glow plug, such as chafing, high resistance or a partial shortpossible
Poor earth or power supply affecting the glow plug circuitpossible
Fault in the glow plug control module or output stage for that channelpossible
Outdated or faulty control unit software where the manufacturer has documented a known issue for that enginerare

How to diagnose

Read all stored and pending codes and freeze frame data, noting engine temperature and battery voltage when the fault set; look for other glow plug codes.
Check the battery condition and charging voltage, as low voltage can upset glow plug current monitoring.
Visually inspect the cylinder 8 glow plug connector, terminal and wiring for corrosion, heat damage, chafing or looseness.
Confirm which glow plug is cylinder 8 for this engine using the manufacturer's data, as numbering and layout vary by model.
Measure the glow plug resistance and compare it with the manufacturer's specification, ideally with the plug disconnected.
Check the supply voltage, earth and wiring continuity between the glow plug and the control module, looking for high resistance or shorts.
Use a scan tool to activate the glow plugs if supported and watch the current or duty cycle for the cylinder 8 channel.
If the plug and wiring test fine, check for applicable software updates and test the glow plug control module according to the manufacturer's procedure.

How to fix

Replace the cylinder 8 glow plug, and consider replacing the set if they are old and of similar age.
Clean or replace the corroded or damaged connector and terminal.
Repair or replace damaged wiring and restore good connections and earths.
Replace the glow plug control module only once the plugs, wiring and supply have been proven good.
Update the control unit software only where a known fault with the existing calibration applies to the engine.

Can I keep driving?

Low severity

The car can normally be driven, but cold starting may be poor and emissions may rise. Book it in soon, especially before cold weather, and take care when removing old glow plugs as they can seize or snap.

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