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 B101D 00: ECU Internal Failure

### Circuit/System Description

When the ignition is turned ON, the passenger presence system (PPS) module performs tests to diagnose critical malfunctions within itself. When the PPS module has completed the power-up mode, the module will establish communication with other modules. When an internal fault is detected, the PPS module will set DTC B101D, and communicate with related modules of an internal fault present.

### Conditions for Running the DTC

The ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

The PPS module has detected an internal electrical malfunction.

### Action Taken When the DTC Sets

PPS functions are disabled.

### Conditions for Clearing the DTC

• | The condition for setting the DTC is no longer present.

• | A history DTC clears after 100 malfunction-free ignition cycles.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

SIR System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Connector Repairs

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Verify that DTC B101D is not set.

⇒ | If the DTC is set, replace the PPS module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PPS replacement, setup, and programming