Circuit Description
The PCM EPROM contains data which is essential in running the engine and transaxle. DTC P0601 checks the integrity of this data. The EPROM data is divided into two halves or sides in the EPROM. The integrity of the data is checked by adding up the data in all locations of the EPROM. This is called the checksum. If the checksum does not equal what it should, then DTC P0601 is set.
Conditions for Setting the DTC
Test Condition
Test continuously.
Failure Condition
The checksum indicates a data failure.
Action Taken When the DTC Sets
| • | Flashing of the PCM is not allowed. |
| • | The PCM will illuminate the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail. |
| • | A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. |
| • | A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test. |
| • | Use a scan tool to clear DTCs. |
| • | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. |
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | |
Replace the PCM. Refer to PCM Replacement/Programming . Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- |
