B1004 GMC Possible Causes
- Faulty Control Module
- Control Module harness is open or shorted
- Control Module circuit poor electrical connection
First diagnose B1004 GMC code
Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.
B1004 GMC Tech NotesThis Diagnostic Trouble Code (DTC) may be stored as history without affecting the operation of the module. If DTC is stored only as history and not current, do not replace the module. DTC will never set as current during testing unless a non-recoverable memory failure. Intermittent interruptions to either hot at all times supply or processor ground will cause the module to set DTC. If this DTC is retrieved as both current and history, replace the module that set DTC.
Cost of diagnosing the B1004 GMC code
Labor: 1.0The cost of diagnosing the B1004 GMC code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
B1004 GMC Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B1004 GMC MeaningThis fault is internal. No external circuits are involved. Module microprocessor must be active/awake for the Diagnostic Trouble Code (DTC) to set. The microprocessor calculates the checksum on those areas of memory that hold critical operation data. This is done at a regular interval and is called a periodic checksum. The microprocessor also calculates a checksum on these memory locations whenever new data is written to them. This is called the running checksum. The microprocessor compares periodic checksum to running checksum. If they do not match, the microprocessor sets DTC B1004.
When DTC is set, microprocessor reverts back to base programmed critical operating data until new data is learned and stored in Keep Alive Memory (KAM). DTC will clear when the microprocessor calculates a successful comparison of periodic checksum to running checksum.
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