GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1999 🢒 Park Avenue 🢒 Body and Accessories 🢒 Doors 🢒 DTC B1658 EEPROM Checksum Error

Circuit Description

The memory seat module (MSM) calibrations are stored in the electrically erasable programmable read only memory (EEPROM). When the ignition is first turned ON, the MSM completes the following actions:

    • Performs internal tests on the EEPROM
    • Determines the integrity of the non-volatile memory

The MSM compares the previously stored checksum with the checksum calculated when the ignition is first turned ON. If the 2 checksums do not match, the MSM indicates a calibration malfunction (checksum error) is current.

Conditions for Setting the DTC
    • The stored checksum does not match the calculated checksum.
    • The MSM detects an internal memory malfunction (checksum error).
    • The condition must occur when the ignition is first turned ON.

Action Taken When the DTC Sets
    • Stores a DTC B1658 in the MSM memory.
    • No driver warning message displays for this DTC.
    • The MSM uses 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 MSM no longer detects an internal memory malfunction (checksum error).
    • A history DTC clears after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Use a scan tool.

Diagnostic Aids

You may need to replace the MSM because of the following factors:

    • You cannot remove the EEPROM from the MSM.
    • DTC B1658 is an internal MSM malfunction.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Perform the entire power seat systems diagnostic system check before you continue with the diagnosis of this diagnostic trouble code (DTC).

    2.

  2. Clear all of the DTCs. Cycle the ignition in order to ensure that the DTC did not falsely set.

    3.

  3. Clear all of the DTCs after you complete the repair procedure.

Step

Action

Value(s)

Yes

No

1

Did you perform the Power Seat Systems Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Power Seat Systems

2

  1. Turn the ignition switch to the ON position.
  2. Clear any DTCs. Refer to Diagnostic Trouble Code (DTC) Clearing .
  3. Turn the ignition switch to the OFF position.
  4. Turn the ignition switch to the ON position.

Is the DTC still present?

--

Go to Step 3

Go to Diagnostic System Check - Power Seat Systems

3

Replace the memory seat module (MSM). Refer to Memory Seat Control Module Replacement .

Did you complete the repair?

--

Go to Step 4

--

4

  1. Turn the ignition switch to the OFF position.
  2. Reconnect or install any of the connectors or the components that were disconnected or removed.
  3. Turn the ignition switch to the ON position.
  4. Clear any DTCs. Refer to Clearing DTCs.

Are all of the DTCs cleared?

--

Go to Diagnostic System Check - Power Seat Systems

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