P06CFCylinder 11 Glow Plug Incorrect
The glow plug control module has determined that the glow plug installed in cylinder 11 does not match the expected type, based on its electrical signature.
Definition
On diesels with per-cylinder glow plug monitoring, the control module profiles each plug's resistance and heating-current curve and compares it with the plug specified in its calibration. P06CF sets when the cylinder 11 plug's signature indicates an incorrect type or voltage rating, most commonly after the wrong replacement part was installed. The module may derate or disable the channel, causing hard cold starts and cold smoke with a glow plug lamp or MIL, and a mismatched plug driven at full duty can overheat and fail.
Common causes
- Wrong voltage-rating or wrong-type glow plug installed in cylinder 11
- Non-OE aftermarket plug with different electrical characteristics
- Heavily degraded plug reading as an incorrect part
- Circuit resistance from a corroded terminal skewing the measurement
- Incorrect or miscoded glow plug control module variant
Common misdiagnoses
- Replacing the glow plug control module instead of the mismatched plug
- Harness repairs when the plug rating is wrong
- Replacing all plugs when only cylinder 11 is incorrect
- Battery replacement for a plug-signature fault
Troubleshooting steps
1.Verify the installed part
Check the cylinder 11 plug part number against the OE catalog for this engine's glow system voltage.
2.Measure resistance
Measure the plug cold and compare with specification and sibling cylinders to identify a mismatch.
3.Inspect connections
Confirm clean, tight terminals and undamaged harness so resistance is not corrupting the module's profiling.
4.Compare heating current
Amp-clamp cylinder 11 during pre-heat and compare the current profile to a known-good cylinder.
5.Install the correct plug
Fit the OE-specified plug torqued to spec (typically 10-15 Nm).
6.Confirm the repair
Clear codes and cycle pre-heat several times to verify the code does not return.