P0607: built-in self-tests and memory error counters

P0607 is controller performance in the generic dictionary. In the cited GM ECM and TCM sections it concerns processor integrity, including online and offline built-in self-test results and error-correction checks for flash and RAM.

Two forms of evidence

The built-in self-test path evaluates five background-task counts. The memory paths instead accumulate hardware-reported error-correction test errors during controller initialization when an error occurred since the previous initialization. Thus, an event may reflect accumulated internal history rather than a simple continuously visible sensor fault.

The tables distinguish a count of three associated with MIL reporting from a count of five associated with MIL reporting and remedial action. This distinction explains why the same broad code need not imply an identical controller response at every stage. It is not a prediction of a particular drivability symptom.

Verification needs the right controller

P0607 appears in both ECM and TCM sections with analogous logic. Identify the actual storing module and retain additional internal-fault information before selecting a service procedure. Reading the code through the powertrain diagnostic interface does not by itself make it an ECM-only problem.

A clean instant after erasing the fault does not reproduce initialization history or complete all background self-tests. Verification should establish that the applicable internal checks pass through the required operation and power-cycle conditions. The source describes diagnostic decisions, not an automatic instruction to reflash or replace the controller.

Source and applicability

Documented monitors in gm-2025-03a, model year 2025. These are module/calibration examples; vehicle, engine and transmission applicability must be confirmed independently. GM 2025-03a, page 363. GM 2025-03a, page 1087.