Failed glow plug on cylinder 7 (resistance or current out of range); Damaged, corroded or loose glow plug connector or terminal on cylinder 7; Wiring fault between the glow plug control unit and plug 7 (chafing, high resistance, short or open circuit); Faulty glow plug control module or output driver for that channel; Low battery voltage or poor supply or earth connections affecting glow plug current; Outdated or faulty control unit software, where the manufacturer lists it as a known cause.

P06CB

Cylinder 7 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
CB: FaultThe specific fault in that area

What it means

P06CB is the generic code for an incorrect glow plug on cylinder 7. The engine or glow plug control unit has seen the glow plug 7 circuit or its feedback (such as current draw, resistance or diagnostic signal) outside the expected range. How the fault is detected and which cylinder is number 7 depend on the engine, so check the vehicle-specific data. This code only applies to engines with at least seven cylinders and individually monitored glow plugs.

Symptoms

Hard starting or extended cranking on cold mornings
White smoke or rough running for the first minutes after a cold start
Engine management or glow plug warning light on
Misfire or uneven idle on cylinder 7 when cold
Slightly higher emissions or fuel use until the engine warms up
No noticeable symptoms when the engine is warm

Possible causes

Failed glow plug on cylinder 7 (resistance or current out of range)likely
Damaged, corroded or loose glow plug connector or terminal on cylinder 7likely
Wiring fault between the glow plug control unit and plug 7 (chafing, high resistance, short or open circuit)possible
Faulty glow plug control module or output driver for that channelpossible
Low battery voltage or poor supply or earth connections affecting glow plug currentpossible
Outdated or faulty control unit software, where the manufacturer lists it as a known causerare

How to diagnose

Read all stored codes and freeze frame data, noting coolant temperature, battery voltage and whether other glow plug codes are present
Check battery condition and charging voltage, as low voltage can disturb glow plug diagnostics
Visually inspect the glow plug 7 connector, wiring and the control unit connector for damage, heat, corrosion or water
Check the glow plug supply and earth connections and the relevant fuses or relays for the glow plug system
Measure the resistance of glow plug 7 and compare it with the other plugs and the manufacturer's specification
Using a scan tool with live data or an actuator test, command the glow plugs and compare current or status for cylinder 7 with the others
Check the wiring from the control unit to plug 7 for continuity and shorts to earth or supply
Check for applicable software updates or technical bulletins for the engine before replacing the module

How to fix

Replace the faulty glow plug on cylinder 7, taking care to follow the manufacturer's removal and torque procedure
Repair or replace the damaged connector, terminal or wiring on the circuit to plug 7
Restore good battery condition, supply and earth connections
Replace the glow plug control module only after the plugs and wiring have been proven good
Apply a manufacturer calibration update if a known software fault applies to the vehicle
Clear the code and road test, then recheck for the code returning after a cold start

Can I keep driving?

Low severity

The car can usually be driven while you arrange a repair, but cold starting may be poor and emissions higher. Book it in soon, as a seized or broken glow plug can be costly to remove, and a persistent misfire needs prompt attention.

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