For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Powertrain On Board Diagnostic (OBD) System Check prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptors
DTC 51: Control Module Calibration Checksum FailureDescription
This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed.
The ECM monitors its ability to read and write to the memory. It also monitors a timing function.
Circuit/System Testing
Ignition ON, clear the DTC information with a scan tool. Observe the scan tool DTC information. Verify that DTC 51 does not fail this ignition cycle.
| ⇒ | If DTC 51 failed this ignition, reprogram the ECM. Refer to Engine Control Module Replacement . If DTC 51 resets, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Engine Control Module Replacement for ECM replacement, programming and setup
