Circuit Description
The module calibrations are stored in the EEPROM. When the ignition is first turned ON, the module performs internal tests on the EEPROM to determine the integrity of its non-volatile memory. The module compares its previously stored checksum with the checksum calculated when the ignition is first turned ON.
Conditions for Setting the DTC
| • | The stored checksum does not match the calculated checksum. |
| • | The condition must occur when the ignition is first turned ON. |
Action Taken When the DTC Sets
| • | The module stores a DTC B1658 as current. |
| • | No driver warning message is displayed for this DTC. |
| • | The module will use default values for any memory address in the EEPROM that is corrupt. |
Conditions for Clearing the DTC
| • | This DTC requires an ignition cycle in order to change from current to history. |
| • | The module no longer detects an internal memory malfunction (checksum error). |
| • | A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | Use a scan tool. |
Diagnostic Aids
Since the EEPROM cannot be removed from the module and DTC B1658 is an internal module malfunction, the module may need to be replaced.
Test Description
The numbers below refer to the step number on the diagnostic table.
-
Perform the Power Door Diagnostic System Check.
-
Clear all of the DTCs and cycle the ignition in order to verify that the DTCs did not falsely set.
-
Clear all of the DTCs after the repair procedure is complete.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the Power Door Systems Diagnostic System Check performed? | -- | Go to Step 2 | ||
Is the DTC still present? | -- | Go to Step 3 | Go to Step 4 | |
3 | Replace the memory mirror module (MMM). Refer to Memory Mirror Module Replacement . Is the repair complete? | -- | Go to Step 4 | -- |
Is the repair complete? | -- | -- |
