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 B0001: Vehicle Speed Information Circuit Range/PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Vehicle Speed Signal Circuit | P0608* | P0608* | P0608* | B0001 |
*. Speedometer and/or Odometer Inaccurate or Inoperative | ||||
Circuit/System Description
The radio receives a vehicle speed signal from the electronic brake control module (EBCM) in order to correlate actual vehicle speed to the movement of the vehicle calculated by the navigation system and reported serial data
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 mph) after receiving a global positioning system (GPS) signal. |
Conditions for Setting the DTC
The navigation radio compares the vehicle speed signal from the ECM to the GPS location signal every second. If the GPS signal indicates that the vehicle has traveled 4 km (2.5 mph) 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 ECM is unavailable.
The following symptoms may happen if the vehicle speed signal from the 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. |
Conditions for Clearing the DTC
| • | A current DTC clears when the navigation radio detects the vehicle speed signal from the ECM for more than one second. |
| • | A history DTC clears after 50 ignition cycles without a vehicle speed signal failure. |
Reference Information
Schematic Reference
| • | Engine Controls Schematics for the 6.0L engine |
| • | Engine Controls Schematics for the 7.0L engine |
Connector End View Reference
| • | Engine Control Module Connector End Views for the 6.0L engine |
| • | Engine Control Module Connector End Views for the 7.0L engine |
Description and Operation
Navigation System Description and Operation
Electrical Information Reference
Circuit/System Testing
Note: The drive wheels of the vehicle must be raised and the transmission must be placed in drive or first gear. Refer to Lifting and Jacking the Vehicle.
- Ignition OFF, disconnect the C2 harness connector at the radio.
- Engine ON, drive wheels raised, place the vehicle in drive or first gear. With a scan tool, verify the speedometer value matches the scan tool vehicle speed parameter in the ECM engine data list.
| ⇒ | If the speedometer matches the scan tool vehicle speed parameter, test the vehicle speed signal circuit terminal D for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the radio. |
| ⇒ | If the speedometer does not match the scan tool vehicle speed parameter, refer to Speedometer and/or Odometer Inaccurate or Inoperative. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for Radio replacement, setup, and programming
