Short to battery voltage in the cylinder 12 glow plug control wiring; Faulty or shorted cylinder 12 glow plug; Damaged, corroded or loose connector or terminal at the glow plug or control module; Fault in the glow plug control module output driver, for example a stuck-on output; Chafed or heat-damaged harness near the cylinder 12 side of the engine; Faulty engine control unit or outdated software where the manufacturer lists it as a known cause.

P06E3

Cylinder 12 Glow Plug Control Circuit High.

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
E3: FaultThe specific fault in that area

What it means

P06E3 is the SAE J2012 generic code for a high condition in the cylinder 12 glow plug control circuit. The engine control unit (or glow plug control module) monitors the voltage or feedback on the glow plug output for that cylinder and saw a level higher than expected, such as a short to voltage, or a circuit state that does not match the commanded state. This code only applies to engines with at least 12 cylinders, and cylinder numbering and circuit layout depend on the engine.

Symptoms

Glow plug warning light on or engine management light on
Hard starting or extended cranking when cold
White or grey smoke and rough running on a cold start
Misfire on cylinder 12 until the engine warms up
Slightly increased emissions or fuel use during warm-up
Possible limp mode on some applications

Possible causes

Short to battery voltage in the cylinder 12 glow plug control wiringlikely
Faulty or shorted cylinder 12 glow pluglikely
Damaged, corroded or loose connector or terminal at the glow plug or control modulepossible
Fault in the glow plug control module output driver, for example a stuck-on outputpossible
Chafed or heat-damaged harness near the cylinder 12 side of the enginepossible
Faulty engine control unit or outdated software where the manufacturer lists it as a known causerare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting engine temperature and battery voltage when the fault set, and check for other glow plug codes.
Check the battery condition and charging voltage, as low or unstable voltage can upset the circuit monitoring.
Visually inspect the glow plug wiring, connector and harness for chafing, melting, corrosion, water ingress and signs of a short to a live feed.
Check the manufacturer's information for the engine to identify the cylinder 12 glow plug location and the control module wiring layout.
With the ignition off and the connector unplugged, measure the glow plug resistance and compare it with the specification for that engine.
Check the control wire for a short to voltage with the control module connected and disconnected, following the wiring diagram.
Use a scan tool's active test, if available, to command the glow plugs and watch the circuit status and current for cylinder 12.
If wiring and the glow plug are good, test the glow plug control module power, earth and output signals before suspecting the module.

How to fix

Repair or replace the harness section that is shorted to voltage, and secure it clear of heat and sharp edges.
Replace the faulty cylinder 12 glow plug, and consider replacing the full set if they are old or the engine is high mileage, in line with manufacturer advice.
Clean or replace corroded or damaged connectors and terminals, and ensure good contact and sealing.
Replace the glow plug control module if its output is confirmed faulty.
Update the control unit software only if the manufacturer lists an outdated calibration as a known cause, then clear the code and retest.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but cold starting and running may suffer, and a short to voltage could damage the glow plug or module. Get it checked soon, and avoid it if it runs very roughly or goes into limp mode.

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