When performing diagnosis on a vehicle for several Engine Control Module (ECM)-related DTCs, it’s critical to check for conditions that may cause low battery voltage or a momentary loss of power or ground to the ECM. Verify that there are not any power or ground concerns before replacing the K20 ECM.
A high number of ECMs with no trouble found have been replaced on vehicles equipped with the 5.3L V8 engine (RPO L83) and 1.5 4-cylinder engine (RPO LFV). (Fig. 18)
Fig. 18
The following ECM DTCs may be set:
DTC P0601 Control Module Read Only Memory Performance
DTC P0602 Control Module Not Programmed
DTC P0603 Control Module Long Term Memory Reset
DTC P0604 Control Module Random Access Memory Performance
DTC P0606 Control Module Processor Performance
DTC P062B Control Module Fuel Injector Control Performance
DTC P062F Control Module Long Term Memory Performance
DTC P0630 VIN Not Programmed or Mismatched – ECM
DTC P16F3 Control Module Redundant Memory Performance
DTC P262B Control Module Power Off Timer Performance
These DTCs are related to internal microprocessor integrity conditions in the ECM as well as incomplete ECM programming.
If any of these DTCs are set, verify that the battery cables are clean and tight and that the battery is fully charged. In addition, check that all ECM power and ground supply circuits do not have an open or high resistance and that there are not any connection or terminal tension issues. Low voltage or a temporary loss of power or ground to the ECM may cause a DTC to set.
TIP: The ECM can withstand normal current draws that are associated with vehicle operations. However, avoid overloading any of these circuits when testing for opens or shorts. Do not ground or apply voltage to any of the ECM circuits unless called out in the appropriate Service Information diagnostic procedures. These circuits should only be tested with a DMM unless the diagnostic procedure instructs otherwise.
– Thanks to Tracy Lucas
