P067E: cylinder 6 low-circuit detection has a startup branch

P067E identifies a low-circuit condition on the cylinder 6 glow-plug channel in the GM source used here. The table is more specific than the short dictionary label: it describes a ground-short test and a separate check for excessive current during initial energization.

Startup evidence can be important

The inrush-current check runs at key-on once per driving cycle. If the initial current profile exceeds its permitted envelope, the diagnostic can report the same low-circuit fault as the ground-short mechanism. A later steady-state reading therefore cannot, by itself, disprove the original fault event.

For ground-short recognition, the published hardware parameters are 0.11 ohm for detection and 0.19 ohm as a boundary above which a short should not be detected. These values concern circuit impedance relative to the controller's ground reference; they do not authorize substituting a bench resistance check for the complete diagnostic.

Operating window

The running branch requires the glow system to be enabled, battery voltage in range, no supply-circuit fault, and an active diagnostic system. Cranking is excluded. The commanded duty cycle must lie between 2.5% and 97.5%, and failure accumulation uses 10 samples out of 20 at 100-millisecond intervals.

Verification should distinguish whether the original evidence arose at startup or during enabled operation. The source lists Type B, two-trip reporting with the glow lamp on. It supplies no failure-frequency ranking or plug replacement instruction. Engine and vehicle applicability must be confirmed against service information before applying these calibration-specific facts.

Source: GM monitor, PDF page 1248.