For 1990-2009 cars

### Circuit Description

The vehicles control modules perform a self-test when the ignition is turned on. If a control module senses an internal error, DTC B1000 is set in that module.

### Conditions for Running the DTC

The ignition switch is turned on.

### Conditions for Setting the DTC

Any of the following conditions may set this code:

• | An internal memory error

• | An internal EEPROM checksum error

• | An internal EEPROM write error

• | An internal voltage regulation error

### Action Taken When the DTC Sets

• | The SERVICE VEHICLE SOON indicator illuminates.

• | The check gages chime sounds.

### Conditions for Clearing the DTC

• | A current DTC B1000 will clear when the code setting condition is no longer present.

• | A history DTC will clear if the condition is no longer present after 100 ignition cycles with no current codes active during the 100 ignition cycles.

### Test Description

The number below refers to the step number on the diagnostic table.

1. If DTC B1000 is set as current, replace the BCM.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check for the system exhibiting the symptom? | Go to Step 2 | Go to Control Module References for the applicable Diagnostic System Check
2 |

1. Install the scan tool.
2. Turn On the ignition with the engine Off.
3. Retrieve the DTCs.

Is the DTC retrieved as a current DTC?

Go to Step 3

Go to Diagnostic Aids

3 | Replace the module. Refer to Control Module References for the applicable replacement procedure. Did you complete the replacement? | Go to Step 4 | --
4 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the conditions for running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK