Failed or degraded glow plug on cylinder 12 (open circuit, high resistance or shorted element); Corroded, loose or damaged glow plug connector or terminal on cylinder 12; Damaged wiring between the glow plug control module and the cylinder 12 glow plug (chafing, break, short to earth or supply); Faulty glow plug control module or driver output for that channel; Poor power or earth supply to the glow plug system, such as a corroded feed or weak battery; Fault in the control unit itself or an outdated calibration, where the manufacturer has documented one.

P06D0

Cylinder 12 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
D0: FaultThe specific fault in that area

What it means

P06D0 means the engine control unit has judged the glow plug for cylinder 12 to be operating incorrectly. It compares the electrical behaviour it sees, such as current draw, resistance or feedback from the glow plug driver, against what it expects, and it set the code when the two did not match. The exact test and the cylinder numbering vary by manufacturer and engine, so check the model-specific data before replacing anything.

Symptoms

Engine management warning light on, and possibly a glow plug warning light
Longer cranking or hard starting when cold
White or grey smoke and rough running just after a cold start
Slight misfire or uneven idle until the engine warms up
Increased fuel use or noise on cold start

Possible causes

Failed or degraded glow plug on cylinder 12 (open circuit, high resistance or shorted element)likely
Corroded, loose or damaged glow plug connector or terminal on cylinder 12likely
Damaged wiring between the glow plug control module and the cylinder 12 glow plug (chafing, break, short to earth or supply)possible
Faulty glow plug control module or driver output for that channelpossible
Poor power or earth supply to the glow plug system, such as a corroded feed or weak batterypossible
Fault in the control unit itself or an outdated calibration, where the manufacturer has documented onerare

How to diagnose

Read all stored and pending codes, and record the freeze frame data including coolant temperature, battery voltage and engine state
Check for other glow plug codes, as several plugs or a module fault points away from one plug
Confirm the cylinder 12 location for this engine from the workshop data, then inspect the plug connector, terminal and wiring for corrosion, heat damage, chafing or water
Check battery condition and the supply and earth to the glow plug module and system
With the engine cold, measure the glow plug resistance and compare it with the specification for that engine
Measure the supply voltage and current draw at the glow plug during a heat cycle, using live data or a suitable meter, as the procedure allows
Test the wiring for continuity and for shorts to earth or supply between the module and the plug
Check for any manufacturer service information or calibration updates relating to this code for the specific model

How to fix

Replace the faulty cylinder 12 glow plug, using the correct specification and tightening to the stated torque
Repair or replace damaged wiring, terminals or the connector
Clean and secure power and earth connections, and charge or replace a weak battery
Replace the glow plug control module if the driver output is proven faulty
Apply a manufacturer-issued calibration update only if service information lists it as a fix for this fault
Clear the code after repair and confirm it does not return after a cold start and heat cycle

Can I keep driving?

Low severity

The car can usually be driven, but book it in soon, as cold starting and cold-running emissions may be poor. If the engine starts badly, runs roughly or smokes heavily, have it checked promptly.

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