What Does P067C Mean?
The PCM has detected a low voltage condition on the glow plug control circuit for cylinder 5. This suggests a short to ground in the glow plug element or its wiring, causing excessive current draw. On a diesel engine, this cylinder may not receive proper pre-heat during cold starts, and the driver may notice rough cold idle, extended crank times, or misfire-like symptoms when cold.
Common Causes
40%
Cylinder 5 glow plug internally shorted to ground
25%
Wiring harness short to ground between GPCM and cylinder 5
20%
Glow plug control module output driver failure
10%
Corroded connector allowing moisture ingress and ground path
5%
PCM signal circuit fault
Diagnostic Steps
1
Measure the resistance of the cylinder 5 glow plug with a multimeter; a reading near 0 ohms or significantly below spec (0.5-2.0 ohms) indicates an internal short.
2
Disconnect the glow plug and check the harness wire from the GPCM to cylinder 5 for shorts to ground; resistance to chassis ground should exceed 10k ohms.
3
Visually inspect the wiring along the valve cover and exhaust manifold area for heat damage, melted insulation, or chafing against metal components.
4
With the glow plug disconnected, activate the GPCM and verify battery voltage is present at the GPCM connector output terminal for cylinder 5.
5
If the glow plug and wiring test good, monitor GPCM current draw on cylinder 5 output with a current clamp during activation to isolate the module.
Estimated Repair Cost
$50 - $400
Parts + labor, varies by vehicle and location
The PCM has detected a low voltage condition on the glow plug control circuit for cylinder 5. This suggests a short to ground in the glow plug element or its wiring, causing excessive current draw. On a diesel engine, this cylinder may not receive proper pre-heat during cold starts, and the driver m...
The most common cause of P067C (Cylinder 5 Glow Plug Control Circuit Low) is: Cylinder 5 glow plug internally shorted to ground
Typical repair costs for P067C range from $50 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive once the engine is running and warmed up. Cold starting reliability will be reduced, and if the short is drawing excessive current, it could blow the glow plug fuse or overload the GPCM, potentially affecting all cylinders. Monitor for further degradation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P067C 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
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