Damaged, corroded or loose wiring or connectors at the glow plug control module 2 (power, earth or signal); Low battery voltage or a poor charging system causing the module to report a fault; Failed or high-resistance glow plugs overloading or upsetting the module's diagnostics; Faulty glow plug control module 2 (internal failure); Blown fuse or faulty relay in the module's supply; Communication fault between the module and the engine control unit (data line or network problem); Outdated or faulty control unit software on a model with a known issue.

P06F5

Glow Plug Control Module 2.

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
F5: FaultThe specific fault in that area

What it means

P06F5 is a generic powertrain code relating to Glow Plug Control Module 2, the second glow plug control module fitted to some diesel engines. The engine control unit has logged a fault with that module or its circuit, such as a wrong or missing signal, a communication problem or an internal fault. The exact trigger and which bank or cylinders the module serves depend on the vehicle, so check the manufacturer's data for the model.

Symptoms

Engine management warning light or glow plug warning light on
Hard starting or extended cranking, especially when cold
White or grey smoke and rough running just after a cold start
Misfire or uneven idle until the engine warms up
Reduced power or limp mode in some cases
Other glow plug circuit codes stored alongside

Possible causes

Damaged, corroded or loose wiring or connectors at the glow plug control module 2 (power, earth or signal)likely
Low battery voltage or a poor charging system causing the module to report a faultlikely
Failed or high-resistance glow plugs overloading or upsetting the module's diagnosticspossible
Faulty glow plug control module 2 (internal failure)possible
Blown fuse or faulty relay in the module's supplypossible
Communication fault between the module and the engine control unit (data line or network problem)possible
Outdated or faulty control unit software on a model with a known issuerare

How to diagnose

Read all stored and pending codes and note freeze frame data, including engine temperature and battery voltage when the code set
Check for related codes such as individual glow plug circuit faults or network communication codes, and diagnose those first
Test battery condition and charging voltage, and make sure terminals are clean and tight
Inspect the module's wiring, connectors, fuses and relay for damage, corrosion, water ingress or heat damage
Check power and earth feeds at the module connector under load against the manufacturer's data
Look at live data to see glow plug commands and module status during a cold start, as supported on the model
Measure glow plug resistance or current draw as specified for the engine and compare against the data
Check for manufacturer service bulletins or software updates relevant to the vehicle

How to fix

Repair or replace damaged wiring, connectors, fuses or relays and clean any corroded earth points
Restore battery and charging system health if voltage is low or unstable
Replace any failed glow plugs, following the correct torque and procedure for the engine
Replace glow plug control module 2 if it is confirmed faulty, and code or adapt it if the model requires
Repair the data line fault if communication is lost
Apply a software update only if the manufacturer lists it as a fix for this fault

Can I keep driving?

Medium severity

The car can usually be driven short-term, but cold starts may be poor and the fault may worsen or cause limp mode. Get it diagnosed soon, especially before cold weather.

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