P06CDCylinder 9 Glow Plug Incorrect
The glow plug control module has determined that the glow plug installed in cylinder 9 does not match the expected type, based on its electrical signature.
Definition
The glow plug control module validates every plug against the specified part by profiling cold resistance and the current ramp during pre-heat. P06CD sets when the cylinder 9 plug's electrical signature indicates a wrong plug type or voltage rating, usually the result of an incorrect replacement during service. The module may limit or disable drive to that plug, producing hard cold starting, cold smoke, and a glow plug lamp or MIL; a wrong high-current plug that continues to be driven risks element overheating and tip damage inside the cylinder.
Common causes
- Wrong voltage-rating or wrong-type glow plug installed in cylinder 9
- Aftermarket plug that does not match the OE electrical characteristics
- Severely degraded plug mimicking an incorrect part
- Terminal or harness resistance distorting the module's measurement
- Wrong-variant or incorrectly coded glow plug control module
Common misdiagnoses
- Replacing the glow plug control module when the plug is the wrong part
- Wiring repairs when the installed plug rating is incorrect
- Replacing the entire plug set when only cylinder 9 is mismatched
- Charging-system parts for a plug-signature fault
Troubleshooting steps
1.Verify the plug part number
Compare the cylinder 9 plug with the OE catalog listing for this engine, confirming voltage rating and element type.
2.Measure cold resistance
Measure plug-to-ground resistance and compare against specification and the other cylinders.
3.Inspect the circuit
Check the terminal, nut, and harness for corrosion or damage adding resistance to the circuit.
4.Profile pre-heat current
Amp-clamp cylinder 9 during a commanded glow cycle and compare with a known-good cylinder's curve.
5.Fit the correct OE plug
Install the specified plug at proper torque (typically 10-15 Nm) after cleaning the bore.
6.Clear and retest
Clear the code and run several pre-heat cycles to confirm the incorrect-plug detection is resolved.