Failed cylinder 6 glow plug (open internal element); Damaged or disconnected electrical connector at the glow plug; Broken or chafed wire in the glow plug control circuit; Corroded or loose ground connection for the glow plug circuit; Faulty glow plug control module or relay; Engine control module software or internal driver fault (rare)

DTC codes / P06xx · Computer and output circuits / P067F

P067FCylinder 6 Glow Plug Control Circuit High

Q: What does code P067F mean?

Cylinder 6 Glow Plug Control Circuit High. P067F indicates that the engine control module has detected an abnormally high voltage on the control circuit for cylinder 6's glow plug, which usually means the circuit is open or the glow plug itself has failed. The computer expects a specific current draw when it commands the glow plug on, and a high-voltage condition tells it that the circuit is not completing the path to ground as designed.

P067F indicates that the engine control module has detected an abnormally high voltage on the control circuit for cylinder 6's glow plug, which usually means the circuit is open or the glow plug itself has failed. The computer expects a specific current draw when it commands the glow plug on, and a high-voltage condition tells it that the circuit is not completing the path to ground as designed.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illumination of the check engine light or glow plug warning lamp
Hard starting or rough idle when the engine is cold
Extended cranking time before the engine fires
White smoke from the exhaust after a cold start
Often no symptoms besides the warning light, especially in warmer weather

Common causes, most likely first

Failed cylinder 6 glow plug (open internal element)
Damaged or disconnected electrical connector at the glow plug
Broken or chafed wire in the glow plug control circuit
Corroded or loose ground connection for the glow plug circuit
Faulty glow plug control module or relay
Engine control module software or internal driver fault (rare)

How to diagnose and fix it

Scan all modules and record freeze-frame data to confirm the code is current and not history
Visually inspect the cylinder 6 glow plug connector and wiring for damage, corrosion, or looseness
Measure the resistance of the cylinder 6 glow plug with a multimeter and compare to the manufacturer's specification
Check for battery voltage at the glow plug connector during the commanded glow period using a test light or multimeter
Perform a voltage drop test on the ground side of the circuit to rule out a bad ground
If the circuit tests good, substitute a known-good glow plug or control module to isolate the fault
Clear the code and verify the repair with a cold-start test and a road test

What a high-voltage glow plug code really means

A high-voltage code on a glow plug circuit almost always indicates an open circuit rather than a short, so the glow plug element or its connector is the most common culprit.
Many glow plug control modules set this code based on current draw rather than actual voltage, so a glow plug that is partially failed can still trigger P067F without a complete open circuit.
Technicians sometimes replace the glow plug only to find the connector terminal has backed out of the housing, so always tug-test the terminal before condemning the plug.
On some vehicles, a weak battery or poor chassis ground can cause the module to misreport a high-voltage condition, so check the basics before chasing the glow plug circuit.
P067F is often stored alongside misfire or glow plug timeout codes, and diagnosing those together can reveal whether the fault is isolated to cylinder 6 or affects the entire glow plug system.

Can I keep driving with P067F?

You can usually drive the vehicle with P067F, but cold starting may be rough and the engine may produce excess smoke until it warms up. Avoid long periods of idling or heavy load immediately after a cold start, and repair the fault before winter to prevent starting problems.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.