What it means
The control circuit driving glow plug control module 2 is open. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Glow plug control module 2 receives a control command through a dedicated circuit so it can manage diesel-engine preheating. P06F6 sets when that control circuit is detected open, interrupting communication or command delivery to module 2.
Common causes
Most likely first.
- Open in control wiring
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Glow plug warning light on (often orange coil symbol)
- Hard cold start or no start in cold weather
- White smoke from exhaust during warm-up
How to diagnose it
- Save freeze-frame data and check for companion glow-plug codes that could help distinguish a control-circuit break from a module supply fault.
- Inspect the module 2 control connector for a pin pushed back, corrosion, water entry, or a loose latch.
- Trace the control wire from the engine controller to module 2 and look for breaks, chafing, or heat damage.
- With the wiring diagram, test continuity through the control circuit and check for an intermittent open while gently moving the harness.
- If the circuit wiring and terminals pass, test the control-module input and engine-controller output using the manufacturer's procedure.
Common fixes
- Reseat a pushed-back terminal and secure the module 2 connector.
- Repair the open or damaged control wire and protect it from further chafing.
- Replace a connector terminal or pigtail that cannot maintain contact.
- Replace module 2 only if its control input is confirmed faulty after the circuit is restored.
Can I keep driving?
The vehicle may run normally once started, but diesel cold starting can become difficult and may produce white smoke during warm-up. Avoid repeated cranking and address the fault before cold conditions make starting unreliable.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.