Medium and Heavy Trucks
Have Truck Repair Questions? Ask an Expert
Hi my name is***** will be glad to try to help.
Fuel Injection Sync Circuit OCC Self Test failed
Check between the battery box and ECM/IDM for corrosion or damage in the harness or connector pins and for a faulty inline fuse. Check the IDM relay and confirm your ECM powers and grounds. If okay inspect the injector harness between the ECM/IDM and injectors for problems. Possible faulty injector can also cause this fault as well. You should have around 870 PSI ICP pressure while cranking while checking with a mechanical 5000 PSI gauge and up to around 4000 PSI with 12 V applied to the IPR to read full pump pressure. Before doing so apply shop air to the ICP port by teeing in to pressure test and listen for leaks in the injector o rings under the valve covers. Let me know
a faulty IDM relay and possible failed ECM could also be the problem. If you have access to a known good ECM, try a test ECM. Let me know
Thanks for the updated info. 253 converts to these code number. Reflash and update the software in the ECM and have it tested.
DTC 621 – Engine using mfg default ratingCondition: Manufacturing defaults selected.Symptoms: Very low power (25 hp).Possible Causes: Programmable parameters for the ECM were never programmed in module.(Usually occurs in new vehicle or new module).Actions: Program ECM.
DTC 622 – Engine using field default ratingCondition: Engine using field default rating.Symptoms: Low power (lowest rating in engine class) and vehicle features not working.Possible Causes: Programmable parameters for the ECM incorrectly programmed in module.Actions: Program ECM.
DTC 623 – Invalid engine EFRCCondition: Invalid EFRCSymptoms: Possible hard start and no start or low power condition.Possible Causes: Wrong EFRC selected for the ECM strategy programmed in the module.Actions: Check the EFRC and verify that it matches the ECM strategy level. Reprogram theECM or change the EFRC as necessary