Failed or degraded glow plug on cylinder 3 (open circuit, high resistance, or short); Damaged, corroded or loose wiring or connector at the cylinder 3 glow plug; Poor power or earth supply to the glow plug circuit, such as a weak battery or corroded terminals; Fault in the glow plug control module output for cylinder 3; Glow plug wiring harness chafed or shorted to earth or supply; Outdated or faulty control unit calibration, where the manufacturer lists it as a known cause for the model.

P06C7

Cylinder 3 Glow Plug Incorrect.

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
C7: FaultThe specific fault in that area

What it means

P06C7 is the generic code for Cylinder 3 Glow Plug Incorrect. The glow plug control module or engine control unit has judged that the glow plug on cylinder 3 is not behaving as expected during pre-heat or post-heat. The measurement it uses (current draw, resistance, or a feedback signal) and the exact limits depend on the engine and the glow plug system fitted.

Symptoms

Engine warning light or glow plug warning light on
Harder starting on cold mornings, especially in low temperatures
Rough running or misfire on cylinder 3 for the first minute after a cold start
White smoke or extra exhaust smell on a cold start
Slightly higher emissions or fuel use until the engine warms up
Other glow plug codes stored alongside it

Possible causes

Failed or degraded glow plug on cylinder 3 (open circuit, high resistance, or short)likely
Damaged, corroded or loose wiring or connector at the cylinder 3 glow pluglikely
Poor power or earth supply to the glow plug circuit, such as a weak battery or corroded terminalspossible
Fault in the glow plug control module output for cylinder 3possible
Glow plug wiring harness chafed or shorted to earth or supplypossible
Outdated or faulty control unit calibration, where the manufacturer lists it as a known cause for the modelrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting engine temperature, battery voltage and whether other glow plug codes are present.
Check the battery condition and charging voltage, and inspect the main power and earth connections for the glow plug system.
Visually inspect the cylinder 3 glow plug connector and wiring for heat damage, corrosion, chafing, or loose pins.
With the engine cold and off, and following the model's procedure, measure the cylinder 3 glow plug resistance and compare it with the other cylinders and the specification.
Check the supply voltage and earth at the cylinder 3 glow plug connector during pre-heat using the manufacturer's procedure.
Use live data, if available, to compare glow plug current or status for each cylinder during pre-heat.
Check the glow plug control module output and its connector, as the test method depends on the engine and system layout.
Search for manufacturer technical bulletins or calibration updates relevant to the vehicle and engine.

How to fix

Replace the cylinder 3 glow plug if it is open circuit, out of specification or shorted, using the correct torque and care to avoid breaking it in the head.
Repair or replace damaged wiring, terminals or the connector for the cylinder 3 glow plug circuit.
Clean and tighten the power and earth connections, and replace the battery if it cannot hold adequate voltage.
Replace the glow plug control module if it is confirmed faulty after the wiring and glow plug have been proven good.
Apply a manufacturer calibration update only if an outdated calibration is confirmed as a known cause for that vehicle.

Can I keep driving?

Low severity

The car can normally be driven, but cold starting may be harder and the engine may run roughly until warm. Book it in soon, particularly before cold weather, and avoid repeated long cranking.

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