Open circuit, chafed or broken wiring between the engine control unit and glow plug control module 2; Corroded, loose or pushed-out pins in the glow plug control module connector or engine control unit connector; Faulty glow plug control module 2 with an internal open circuit; Missing or poor power supply or earth to the module, such as a blown fuse or a bad earth connection; Water ingress or heat damage to the harness near the engine; Fault within the engine control unit driver circuit.

P06F6

Glow Plug Control Module 2 Control Circuit/Open.

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
F6: FaultThe specific fault in that area

What it means

P06F6 means the powertrain control module has detected an open circuit in the control circuit for glow plug control module 2. The glow plug control module is normally commanded and monitored over a wiring circuit, and the fault sets when the expected signal or voltage is missing, indicating a break or very high resistance. Which glow plugs the second module serves, and how the circuit is arranged, depends on the vehicle and engine.

Symptoms

Glow plug or engine management warning light on
Hard starting or long cranking on cold mornings
Rough running or misfire on a cold engine
White or grey smoke from the exhaust after a cold start
Increased exhaust smell or emissions when cold
No obvious symptoms in warm weather

Possible causes

Open circuit, chafed or broken wiring between the engine control unit and glow plug control module 2likely
Corroded, loose or pushed-out pins in the glow plug control module connector or engine control unit connectorlikely
Faulty glow plug control module 2 with an internal open circuitpossible
Missing or poor power supply or earth to the module, such as a blown fuse or a bad earth connectionpossible
Water ingress or heat damage to the harness near the enginepossible
Fault within the engine control unit driver circuitrare

How to diagnose

Read all stored and pending codes and note any other glow plug or module codes, then record freeze frame data including coolant temperature and battery voltage.
Check the battery condition and charging voltage, as low voltage can cause glow plug circuit faults.
Check the fuses and relays that supply glow plug control module 2, using the vehicle wiring diagram for your model.
Visually inspect the harness and connectors at the module and engine control unit for chafing, heat damage, corrosion, water and bent or pushed-out pins.
With the ignition off and the connectors disconnected, test the control wire for continuity and for shorts to earth or supply, using the wiring diagram.
Check the module power supply and earth under load with a multimeter, looking for voltage drop.
Clear the code and run the glow plug system or a cold start cycle, using a scan tool, to see if the fault returns and whether the module responds.
If wiring and supplies are good, check the module itself against manufacturer test procedures, as these depend on the engine.

How to fix

Repair or replace the damaged wiring section, using proper solder and sealed joints or a new harness section.
Clean, repair or replace corroded or damaged connectors and terminals, and ensure they are fully seated.
Replace blown fuses only after finding and fixing the cause of the overload.
Restore a poor power or earth connection by cleaning and tightening it or repairing the cable.
Replace glow plug control module 2 if the circuit tests are good and the module is confirmed faulty, then carry out any adaptation the manufacturer requires.

Can I keep driving?

Medium severity

The car will usually still run, but cold starting may be poor and the glow plug system may not work properly. Get it checked soon, especially before cold weather, and avoid repeated long cranking.

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