For 1990-2009 cars

### Circuit Description

The internal fault detection is handled inside the control module. No external circuits are involved.

### DTC Descriptor

The diagnostic procedure supports the following DTCs:

DTC B1000 Electronic Control Unit (ECU) Performance

The vehicle has DTCs including the DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description .

DTC Symptom | DTC Symptom Descriptor
--- | ---
00 | No Additional Information
31 | General Checksum Error
32 | General Memory Failure
33 | Special Memory Failure
34 | RAM Failure
35 | ROM Failure
36 | EEPROM Failure
37 | Watchdog Processor Failure
38 | Supervision Software Failure
39 | Internal Electronic Failure

### Conditions for Running the DTC

The module runs the program to detect an internal fault when the command is powered. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.

### Conditions for Setting the DTC

#### B1000 00

Any of the conditions detailed below for B1000 31-39

#### B1000 31

Checksum of the EEPROM or Flash memory at powerup is incorrect.

#### B1000 32

Failure to write to Flash Memory during the writing process

#### B1000 33

Failure to write to EEPROM or Flash memory

#### B1000 34

RAM failure

#### B1000 35

• | Failure of the calibration sector of the Flash ROM.

• | Checksum of the Flash Sector is incorrect.

#### B1000 36

Failure of the EEPROM. Checksum is incorrect.

#### B1000 37

Watchdog Processor Failure

#### B1000 38

• | BASS algorithm failure

• | Other software failures

#### B1000 39

• | Internal power supply failure

• | Internal yaw rate sensor failure

• | Internal temperature sensor failure

• | Forward looking sensor error

### Action Taken When the DTC Sets

If DTC B1000 is set as current, the respective module will stop working. Some indications to the driver may be displayed, the module function that sets the code will also be displayed.

### Conditions for Clearing the DTC

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

• | When the ignition cycle counter has reached the newly set threshold and no trouble occurs repeatedly, the history DTC will be cleared.

### Diagnostic Aids

• | This DTC will be stored as a history DTC without affecting the operation of the module. If stored only as a history DTC and not retrieved as a current DTC, do not replace the module.

• | If this DTC is retrieved as both a current and history DTC, replace the module.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Retrieve the DTCs.

Is DTC retrieved as a current DTC?

Go to Step 3

Go to Diagnostic Aids

3 | Replace the module setting the DTC as current. Refer to Control Module References for replacement, setup and programming. Is the replacement complete? | Go to Step 4 | --
4 |

1. Clear the DTCs with the scan tool.
2. Operate the vehicle under conditions when DTC runs as specified in supporting documents.

Does the DTC set again?

Go to Step 2

System OK