What Does P06CA Mean?
The ECM has detected that the cylinder 6 glow plug is operating incorrectly on this diesel engine. This applies to V6, V8, inline-6, or larger diesel configurations. The glow plug has abnormal electrical characteristics or is not reaching the required temperature. Cold starting difficulty, rough idle during warm-up, and white smoke are typical symptoms.
Common Causes
45%
Failed cylinder 6 glow plug — element burnout, high resistance, or carbon fouling
20%
Corroded or damaged wiring/connector to the cylinder 6 glow plug
15%
Glow plug control module output failure for cylinder 6
12%
Poor ground connection affecting cylinder 6 glow plug circuit
8%
ECM internal fault in glow plug monitoring for cylinder 6
Diagnostic Steps
1
Measure cylinder 6 glow plug resistance with connector removed — expect 0.5–2.0 ohms. On inline-6 engines, cylinder 6 is at the rear and may be harder to access.
2
Verify battery voltage at the cylinder 6 harness connector during preheat activation. On V-configuration engines, confirm bank assignment and correct cylinder numbering per manufacturer convention.
3
Inspect the wiring harness for cylinder 6, paying attention to routing near exhaust manifolds and turbo components where heat damage is common.
4
Compare current draw across all glow plugs using a clamp ammeter during the preheat cycle — all should be within 10% of each other.
5
If the glow plug is seized in the cylinder head (common on high-mileage diesels), use penetrating oil and proper extraction tools to avoid breaking the plug off in the head.
Estimated Repair Cost
$80 - $450
Parts + labor, varies by vehicle and location
The ECM has detected that the cylinder 6 glow plug is operating incorrectly on this diesel engine. This applies to V6, V8, inline-6, or larger diesel configurations. The glow plug has abnormal electrical characteristics or is not reaching the required temperature. Cold starting difficulty, rough idl...
The most common cause of P06CA (Cylinder 6 Glow Plug Incorrect) is: Failed cylinder 6 glow plug — element burnout, high resistance, or carbon fouling
Typical repair costs for P06CA range from $80 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive. On a 6+ cylinder diesel, one failed glow plug has a modest impact on starting performance. Cold-weather starts may require slightly longer cranking. Over time, the unheated cylinder contributes to increased particulate emissions and DPF loading.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P06CA 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
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