P0601

Circuit Description
The PCM used in this vehicle utilizes an Electrically Erasable Programmable Read-Only Memory (EEPROM). The EEPROM contains programs information and the calibrations required for powertrain diagnostics operation.
Unlike the PROM used in past applications, the EEPROM is not replaceable. When the PCM is replaced or a calibration update is required, the PCM must be programmed using approved Techline equipment.

Conditions for Running the DTC
Tested continuously during crank or running.

Conditions for Setting the DTC
The PCM detects a problem with internal programming.

Action Taken When the DTC Sets
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic tails. The PCM stores this information in the Freeze Frame and/or the Failure Records.

Conditions for Clearing the MIL/DTC
^ The PCM turns the MIL Oft after three consecutive drive trips that the diagnostic runs and does not fail.
^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after forty consecutive warm-up cycles, if this or any Other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the MIL/DTC.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended.

Diagnostic Aids
DTC P0601 indicates that the contents of the EEPROM have changed since the PCM was programmed. The only possible repair is PCM replacement. Remember to program the replacement PCM with the correct software and calibration for the vehicle.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
2. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.