P06D2: the fifth sensor reference is monitored for low supply voltage

P06D2 is the fifth sensor-reference supply diagnostic in this GM table. The controller monitors the voltage available on that reference circuit. Its generic circuit/open wording should not be read as proof that one particular sensor has an open wire.

A reference circuit is the object of the check

For this calibration, the documented criterion is reference-five voltage at or below 4.6 V. The condition must persist for 0.1 second, with the test running continuously on a 0.01-second cycle when ignition and the basic enabling conditions are satisfied. These are source-specific monitor values, not a substitute for the correct wiring procedure.

The page also lists another reference circuit with a different required duration. That difference is a reason to retain the exact reference identifier and code when reviewing scan data; adjacent reference faults should not be treated as interchangeable just because their nominal supplies are similar.

Find the affected circuit before selecting a component

The summary does not list which sensors share reference five on a particular vehicle. Establish that network from the applicable wiring information, then interpret associated sensor faults in relation to the common supply. Multiple abnormal readings can be consequences of a shared reference problem rather than separate component failures.

The code alone cannot distinguish a harness problem, an attached load or an internal supply fault. Preserve the reference-voltage evidence and operating state, and let the vehicle-specific procedure determine safe isolation tests. Repair confirmation requires a stable reference during a valid monitoring opportunity, not merely a temporary disappearance of the fault after memory is cleared.

Source and applicability

GM 2015 15OBDG09 LML/LGH-common engine-control summary. Only the cited monitor and calibration are described; per-code vehicle and engine applicability has not been established.

15OBDG09 Engine Diagnostics, physical PDF page 126.