What Does P06C7 Mean?
The ECM has determined that the cylinder 3 glow plug is not functioning within acceptable parameters on this diesel engine. The plug may have incorrect resistance, abnormal current draw, or failure to reach target temperature. The driver may experience extended cranking, rough idle after cold start, white smoke from the exhaust, and a glow plug warning light on the dash.
Common Causes
45%
Failed cylinder 3 glow plug due to age, carbon deposits, or internal element failure
20%
Corroded or damaged wiring/connector between the GPCM and cylinder 3 glow plug
15%
Glow plug control module not delivering proper voltage or duration to cylinder 3
12%
High-resistance ground path at the cylinder 3 glow plug or engine block
8%
ECM internal monitoring circuit fault for cylinder 3 glow plug feedback
Diagnostic Steps
1
Remove the electrical connector from the cylinder 3 glow plug and measure resistance across the plug terminals — a healthy plug reads 0.5–2.0 ohms; an open or reading above 6 ohms indicates failure.
2
With the connector disconnected from the plug, key ON with engine cold, verify battery voltage is present at the harness side during the glow cycle. No voltage means a supply-side issue.
3
Inspect the cylinder 3 glow plug connector and wiring for signs of heat damage, oil contamination, or terminal corrosion — diesel engine environments are harsh on wiring.
4
Measure current draw through the cylinder 3 glow plug circuit with a clamp ammeter during preheat — compare against other cylinders. All should draw similar amperage (15–25A initial draw).
5
If all electrical tests pass, consider removing the glow plug for physical inspection — check the tip for excessive carbon buildup, swelling, or cracking that would impair heating performance.
Estimated Repair Cost
$75 - $350
Parts + labor, varies by vehicle and location
The ECM has determined that the cylinder 3 glow plug is not functioning within acceptable parameters on this diesel engine. The plug may have incorrect resistance, abnormal current draw, or failure to reach target temperature. The driver may experience extended cranking, rough idle after cold start,...
The most common cause of P06C7 (Cylinder 3 Glow Plug Incorrect) is: Failed cylinder 3 glow plug due to age, carbon deposits, or internal element failure
Typical repair costs for P06C7 range from $75 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle can be driven safely in warm weather, but cold-start reliability is reduced. If multiple glow plugs are failing simultaneously, the engine may not start at all in cold conditions. Running with failed glow plugs increases unburned fuel in the exhaust, stressing the DPF and catalytic converter over time.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P06C7 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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