Failed glow plug on cylinder 5 (open internal element); Open or damaged wire in the glow plug control circuit for cylinder 5; Corroded or loose electrical connector at the cylinder 5 glow plug; Faulty glow plug control module (GPCM) or relay output for that cylinder; High resistance in the ground circuit for the glow plug; ECM internal driver fault (less common)

DTC codes / P06xx · Computer and output circuits / P067D

P067DCylinder 5 Glow Plug Control Circuit High

Q: What does code P067D mean?

Cylinder 5 Glow Plug Control Circuit High. P067D indicates that the engine control module (ECM) has detected a high-voltage condition on the control circuit for cylinder 5's glow plug. The ECM expects the circuit to pull the voltage low when the glow plug is commanded on, but instead it sees voltage staying near battery positive, indicating an open circuit, a faulty glow plug, or a wiring fault.

P067D indicates that the engine control module (ECM) has detected a high-voltage condition on the control circuit for cylinder 5's glow plug. The ECM expects the circuit to pull the voltage low when the glow plug is commanded on, but instead it sees voltage staying near battery positive, indicating an open circuit, a faulty glow plug, or a wiring fault.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Hard cold starting or extended cranking before the engine fires
Rough idle and white smoke immediately after a cold start
Reduced fuel economy during warm-up
In rare cases, a misfire code for cylinder 5 may accompany P067D

Common causes, most likely first

Failed glow plug on cylinder 5 (open internal element)
Open or damaged wire in the glow plug control circuit for cylinder 5
Corroded or loose electrical connector at the cylinder 5 glow plug
Faulty glow plug control module (GPCM) or relay output for that cylinder
High resistance in the ground circuit for the glow plug
ECM internal driver fault (less common)

How to diagnose and fix it

Clear the code and verify it returns after a cold-start cycle to confirm it is not intermittent
Visually inspect the cylinder 5 glow plug connector and wiring for corrosion, chafing, or loose pins
Measure the resistance of the cylinder 5 glow plug with a multimeter and compare to specifications
Check for voltage on the control circuit with the glow plug commanded on; if voltage is present but the plug does not heat, replace the glow plug
If the glow plug is good, perform a voltage drop test on the control circuit and ground circuit to locate excessive resistance
Test the glow plug control module output for cylinder 5 if the wiring and glow plug pass inspection
Replace the faulty component and recheck for the code after a cold soak

Why a good glow plug still sets P067D

A glow plug that tests good with an ohmmeter can still cause P067D if the control circuit has high resistance at a connector or ground point, because the ECM monitors voltage rather than current.
The code is often set by a poor connection at the glow plug terminal that looks fine visually but has corrosion inside the boot.
On some vehicles, a faulty glow plug control module can set a high-circuit code for one cylinder even when all glow plugs and wiring are intact.
P067D does not always mean the glow plug is bad; the ECM may see high voltage because the control wire is shorted to battery positive, which requires tracing the harness.
Replacing all glow plugs because of one high-circuit code is a common misdiagnosis; always test the individual circuit first.

Can I keep driving with P067D?

You can usually drive the vehicle with P067D, but cold starting may be difficult and the engine may run rough until warm. Avoid heavy loads or long idling during warm-up, and repair the fault before cold weather arrives 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.