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 Descriptor

DTC B2461 00: Navigation Electronic Control Unit (ECU) Synchronous Signal Error

### Circuit Description

The navigation interface module (NIM) communicates with the navigation module via serial data. The NIM can request diagnostic information from the navigation module, if the NIM does not receive a response from the navigation module a DTC will set.

### Conditions for Running the DTC

• | The ignition ON

• | The system voltage is at least 9.5 volts and no more than 15.5 volts.

### Conditions for Setting the DTC

• | When diagnostic information is requested from the navigation module by the navigation interface module (NIM) and a response is not received.

• | DTC U1401 is not set as current

### Conditions for Clearing the DTC

A history DTC clears after 50 fault-free ignition cycles.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Navigation System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Verification

1. Verify DTC U1401is not set.

⇒ | If the DTC is set, refer to DTC U1401

2. Verify DTC B2461 is not set.

⇒ | If the DTC is set, replace the Navigation Module.

### Repair Instructions

Perform the Diagnostic Repair Verification.

Control Module References for navigation module replacement.