What Does P068D Mean?
The PCM has detected a high voltage condition on the cylinder 7 glow plug control circuit, indicating an open circuit or extremely high resistance. The glow plug in cylinder 7 is not heating properly for cold starts. The driver may experience hard starting in cold weather, white exhaust smoke, and rough running during the first few minutes of operation.
Common Causes
40%
Cylinder 7 glow plug element burned open
25%
Open wire in the harness between GPCM and cylinder 7
20%
Corroded or disconnected terminal at cylinder 7 glow plug
10%
GPCM output driver open for cylinder 7
5%
Poor ground return path for the glow plug bank
Diagnostic Steps
1
Measure cylinder 7 glow plug resistance; OL (infinite) confirms the element has burned open. Normal spec is 0.3-2.0 ohms.
2
Check continuity from the GPCM output terminal for cylinder 7 to the glow plug connector to verify the harness is intact.
3
Inspect the bus bar connections to cylinder 7 for corrosion, broken sections, or loose fasteners.
4
Command GPCM activation and measure voltage at the cylinder 7 harness connector; battery voltage should be present during the glow cycle.
5
If the glow plug is seized in the head, apply penetrating oil and allow 24 hours of soak time before attempting removal to avoid breaking the plug.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
The PCM has detected a high voltage condition on the cylinder 7 glow plug control circuit, indicating an open circuit or extremely high resistance. The glow plug in cylinder 7 is not heating properly for cold starts. The driver may experience hard starting in cold weather, white exhaust smoke, and r...
The most common cause of P068D (Cylinder 7 Glow Plug Control Circuit High) is: Cylinder 7 glow plug element burned open
Typical repair costs for P068D range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle is safe to drive once warmed up. Cold-start reliability will be reduced, particularly in freezing temperatures. On multi-cylinder engines, one failed glow plug is less critical than on a 4-cylinder, but should still be repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P068D to identify the root cause.
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Quick Info
Category
Powertrain
System
Diesel Cold Start / Glow Plug System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
