B1656 EEPROM Write Error - Seats

Circuit Description

The memory seat module (MSM) performs internal tests on the EEPROM each time that the MSM performs a write function to a memory address in the EEPROM. The MSM reads the data that was written and compares the written data to the present data. If the data does not match after 3 consecutive write and verify attempts, the MSM will indicate that a write malfunction is current.

Conditions for Setting the DTC

^ The data read after a write does not match the data being written 3 consecutive times.
^ The MSM detects an internal write malfunction.
^ The condition occurs when data is being written.

Action Taken When the DTC Sets

^ The MSM stores DTC B1656 in memory.
^ No driver warning message will be displayed for this DTC.
^ The MSM will store the value being written in another memory address in the EEPROM.

Conditions for Clearing the DTC

^ This DTC requires a successful write in order to change from current to history.
^ The MSM no longer detects an internal write malfunction.
^ A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Use the on-boards clearing DTCs feature.
^ Use a scan tool.

Diagnostic Aids

Since the EEPROM cannot be removed from the MSM and DTC B1656 is an internal MSM malfunction, the MSM may be replaced. Refer to the diagnostic table.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

1. Perform the entire Power Seat Systems Diagnostic System Check before continuing with the diagnosis of this DTC.
2. Clear all DTCs and cycle the ignition in order to check that the DTC did not falsely set.
4. Clear all DTCs after the repair procedure is complete.