For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle 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 P0601: Control Module Read Only Memory (ROM)DTC P1650: Control Module Internal Performance
DTC P1655: Control Module Internal Performance
Circuit/System Description
This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed.
Conditions for Running the DTC
DTC P0601
| • | The ignition is ON, or the engine is operating. |
| • | The DTCs run once an ignition cycle. |
DTC P1650 and P1655
| • | The ignition is ON, or the engine is operating. |
| • | The DTCs run once an ignition cycle. |
Conditions for Setting the DTC
DTC P0601
The ECM detects that the checksum calculation does not match the expected checksum.
P1650 and P1655
The ECM detects a low power counter error for more than 3 seconds.
Action Taken When the DTC Sets
| • | DTC P0601 is a Type A DTC. |
| • | DTC P1650 is a Type C DTC. |
| • | DTC P1655 is a Type B DTC. |
Conditions for Clearing the DTC
| • | DTC P0601 is a Type A DTC. |
| • | DTC P1650 is a Type C DTC. |
| • | DTC P1655 is a Type B DTC. |
Reference Information
Description and Operation:
Engine Control Module Description
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Circuit/System Testing
Ignition ON, observe the DTC information with a scan tool.
| ⇒ | If DTCs P0601, P1650, or P1655 failed this ignition, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM replacement, setup, and programming
