CAT Engine SPN630FMI2 Fault Code: Calibration Memory : Erratic, Intermittent or Incorrect
Also called Calibration Memory : Erratic, Intermittent, or Incorrect
Calibration Memory : Erratic, Intermittent or Incorrect · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 630 FMI 2 means the CAT Electronic Control Module (ECM) has detected that its calibration memory is erratic, intermittent, or incorrect, usually tied to a missing or invalid injector code programmed into the ECM. The engine may run rough at low idle. Fixing it typically requires flash programming the ECM with the correct flash file.
Medium severity. This is not an immediate shutdown condition, but rough idle and incorrect injector calibration can affect engine performance and fuel delivery, so it should be diagnosed before the machine goes back into heavy service.
What does CAT Engine error code SPN630FMI2 mean?
SPN 630 FMI 2 points to a problem inside the ECM's calibration memory. The ECM stores calibration data, including injector codes, that tell it exactly how each injector should fire. When this data is erratic, intermittent, or incorrect, the ECM cannot properly control fuel delivery.
CAT's diagnostic text ties this specifically to injector codes: either an injector code has not been programmed for one or more injectors, or the injector code that is programmed is invalid. Because injector codes calibrate fuel delivery per cylinder, a bad or missing code can cause the engine to run rough, especially at low idle.
The fix path CAT lists for this and related flash-programming issues is to reflash the ECM with the correct flash file using the electronic service tool, then verify configuration parameters and injector codes are properly programmed.
Common causes of SPN630FMI2
- Faulty ECM
- Faulty injector
- Injector code not programmed for one or more injectors
- Injector code programmed for one or more injectors is invalid
How to troubleshoot CAT Engine SPN630FMI2: first checks
- Connect the electronic service tool to the diagnostic connector and check for active and logged diagnostic codes related to injectors or calibration.
- Check the engine serial number and confirm the correct flash file part number is available for this engine, using the Flash File Search tool on the Service Technician Workbench or the Flash Software Files feature on SIS Web if the part number is not already known.
- Access the Configuration screen under the Service menu and check the Tattletale column for each parameter. Any parameter showing a tattletale of 0 needs to be programmed.
- Inspect for rough running at low idle, which CAT lists as a symptom tied to this code, and note whether it is present before and after any reprogramming.
- Verify injector codes are correctly entered for every injector on the engine, since a missing or invalid injector code is a listed cause.
How the code clears
CAT's documented resolution for this code is flash programming the ECM. Connect the electronic service tool to the diagnostic connector, turn the keyswitch to the ON position without starting the engine, then select WinFlash from the Utilities menu. Select the engine ECM under Detected ECMs, browse to and select the correct flash file part number, verify the File Values match the application, and press Begin Flash. If the engine rating is being changed, factory passwords must be obtained before the flash file will be accepted. After flashing, check the Configuration screen for any parameter with a tattletale of 0 and program it. Start the engine, check for proper operation, and confirm there are no active diagnostic codes. If WinFlash will not communicate with the ECM, that points to a separate service tool communication issue rather than this code itself.
Frequently asked questions
What does SPN 630 FMI 2 mean on a CAT engine?
It means the ECM has detected that its calibration memory is erratic, intermittent, or incorrect. CAT ties this specifically to injector codes that are either missing or invalid for one or more injectors.
Can I still run the machine with this code active?
The engine may run, but CAT notes it may run rough at low idle. Since this relates to fuel injector calibration, it's best to diagnose and correct it before extended operation.
What causes SPN 630 FMI 2?
CAT lists a faulty ECM, a faulty injector, an injector code that has not been programmed, or an injector code that has been programmed but is invalid.
How do you fix SPN 630 FMI 2?
The documented fix is flash programming the ECM with the correct flash file using the electronic service tool, then verifying all configuration parameters, especially injector codes, are properly programmed with no parameter left at a tattletale of 0.
Do I need the engine serial number to fix this?
Yes. The engine serial number is needed to search for and confirm the correct flash file part number before flash programming.
What if the electronic service tool won't communicate with the ECM during flashing?
That is treated as a separate issue from this code. CAT directs technicians to the Electronic Service Tool Does Not Communicate troubleshooting procedure in that case.
Is a rough idle always caused by this code?
Not necessarily, but CAT lists rough running at low idle as a condition the ECM associates with this code, tied to incorrect injector calibration.