For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC B1000 00: Electronic Control Unit Performance - No Additional Information
DTC B1000 31: Electronic Control Unit Performance - General Checksum Error
DTC B1000 57: Electronic Control Unit Performance - Expected Reaction After Event Did Not Occur

### Circuit/System Description

The control module runs a program to detect an internal fault when power up is commanded.

### Conditions for Running the DTC

Ignition ON.

### Conditions for Setting the DTC

The control module has detected an internal malfunction.

### Action Taken When the DTC Sets

The control module refuses all additional inputs.

### Conditions for Clearing the DTC

• | A current DTC clears when the malfunction is no longer present.

• | A history DTC clears in all of the modules except the sensing and diagnostic module (SDM), when the ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

• | If the code is set in the SDM it will never clear and the Air Bag indicator will remain illuminated.

### Reference Information

#### Schematic Reference

Data Communication Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Data Link Communications Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool References

Control Module References for scan tool information

### Circuit/System Verification

Verify that DTC B1000 is not set.

⇒ | If the DTC is set, perform the setup procedure on the control module. If the DTC resets replace the control module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, setup, and programming