Diagnostic Instructions
DTC Descriptor
DTC B0001: Vehicle Speed Information Circuit Range/Performance
Circuit/System Description
The navigation radio receives the vehicle speed signal either from the powertrain control module (PCM)/engine control module(ECM), through a dedicated circuit shared with the instrument cluster.
Conditions for Running the DTC
| • | The navigation radio must detect a power mode transition to ON. |
| • | The radio does not set this DTC if B1327 or B1328 is current. |
| • | The vehicle must drive for 4 km (2.5 mi) after receiving a global positioning system (GPS) signal. |
Conditions for Setting the DTC
The navigation radio compares the vehicle speed signal from the PCM/ECM to the GPS location signal every second. If the GPS signal indicates that the vehicle has traveled 4 km (2.5 mi) but no vehicle speed signal was received, the radio sets the
DTC.
Action Taken When the DTC Sets
The navigation radio uses the GPS signal when the vehicle speed signal from the PCM/ECM is unavailable.
The following symptoms may happen if the vehicle speed signal from the PCM/ECM is unavailable:
| • | The vehicle icon may jump to different positions on the map screen. |
| • | The vehicle icon, current position marker may not move on the map screen while the vehicle is being driven. |
| • | The route guidance accuracy may be degraded. |
| • | Turn by Turn navigation may be inoperative. |
Conditions for Clearing the DTC
| • | A current DTC clears when the navigation radio detects the vehicle speed signal from the PCM/ECM for more than one second. |
| • | A history DTC clears after 50 ignition cycles without a vehicle speed signal failure. |
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Entertainment/Communication Connector End Views
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List
Circuit/System Testing
- Ignition OFF, disconnect the radio harness connector X2. Connect a DMM to the vehicle speed signal (VSS) circuit terminal D and ground.
- Ignition ON, operate the vehicle drive wheels at 5 mph. Verify 3-7 Hertz on the VSS circuit.
| ⇒ | If the reading is not as specified, test the VSS circuit for an open, high resistance, short to ground or short to voltage. If the circuit tests normal replace the PCM/ECM. |
- If the circuit tests normal, replace the radio.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PCM/ECM replacement, setup, and programming
