What Does P067B Mean?
The PCM has detected that the glow plug control circuit for cylinder 4 is reading higher voltage than expected. This indicates an open circuit or excessive resistance in the glow plug or its wiring. The driver may experience hard cold starts, excessive cranking time, and white or gray smoke from the exhaust during cold startup.
Common Causes
35%
Open circuit in cylinder 4 glow plug (burned out element)
25%
Open or high-resistance connection in glow plug wiring
20%
Corroded or loose connector at cylinder 4 glow plug
15%
Faulty glow plug control module with open high-side driver
5%
Damaged ground path for glow plug circuit
Diagnostic Steps
1
Measure cylinder 4 glow plug resistance; a reading of OL (open/infinite) confirms a burned-out glow plug. Normal range is 0.5-2.0 ohms.
2
Inspect the glow plug bus bar (if equipped) and individual connector for corrosion, carbon buildup, or loose fitment that would cause high resistance.
3
Perform a voltage drop test on the supply side of the glow plug circuit by commanding GPCM activation and measuring voltage at the glow plug terminal versus at the GPCM output; drop should be less than 0.5V.
4
Check continuity from the GPCM output terminal to the cylinder 4 glow plug connector to rule out an open in the harness.
5
If all wiring checks pass, swap the cylinder 4 glow plug with a known-good cylinder and retest to confirm the glow plug is at fault.
Estimated Repair Cost
$50 - $350
Parts + labor, varies by vehicle and location
The PCM has detected that the glow plug control circuit for cylinder 4 is reading higher voltage than expected. This indicates an open circuit or excessive resistance in the glow plug or its wiring. The driver may experience hard cold starts, excessive cranking time, and white or gray smoke from the...
The most common cause of P067B (Cylinder 4 Glow Plug Control Circuit High) is: Open circuit in cylinder 4 glow plug (burned out element)
Typical repair costs for P067B range from $50 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle can still be driven once running, but cold starts will be unreliable, especially in temperatures below 40°F. Repeated hard cranking can drain the battery and overheat the starter motor. Extended misfiring during cold operation increases unburned fuel in the exhaust, which can damage the diesel particulate filter.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P067B to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
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.
