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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 Seville 🢒 DTC 🢒 DTC B1658 EEPROM Checksum Error

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 and can 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. If the two checksums do not match, the module will indicate a calibration malfunction (checksum error) is current.

Conditions for Setting the DTC
    • The stored checksum does not match the calculated checksum.
    • The module 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 module memory.
    • No driver warning message will be 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 the On-Boards clearing DTCs feature.
    • 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. Refer to diagnostic table.

Test Description

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

  1. Perform the Diagnostic System Check before continuing with the diagnosis of this DTC.

    2.

  2. Clear all DTCs and cycle ignition to check that the DTC did not falsely set.

    3.

  3. Clear all DTCs after the repair procedure is complete.

DTC B1658 -- EEPROM Checksum Error

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Cellular Telephone

2

  1. Turn the ignition switch to ON.
  2. Clear any DTCs. Refer to Clearing DTCs .
  3. Turn the ignition switch to OFF.
  4. Turn the ignition switch to ON.

Is the DTC still present?

--

Go to Step 3

Go to Cellular Telephone System Check

3

Replace the cellular telephone module. Refer to Radio Frequency Booster and Bracket Assembly Replacement .

Is the replacement complete?

--

Go to Step 4

--

4

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

Are all DTCs cleared?

--

Go to Diagnostic System Check - Cellular Telephone

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