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 engine control module (ECM) creates the vehicle speed output signal by pulsing the circuit to ground at a rate of 4 KPPM. The VSS input is pulled high to B+ in the radio. The ECM monitors the voltage at the vehicle speed signal circuit to determine when the voltage is out of the normal operating range.
Conditions for Running the DTC
| • | Vehicle speed must exceed 4 km/h (2.5 mph) after receiving a global positioning system (GPS) signal. |
| • | Engine speed is more than 400 RPM. |
| • | Battery voltage must be between 9-16 volts. |
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 may exhibit the following conditions when a fault is present:
| • | 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
| • | The condition responsible for setting the DTC no longer exists. |
| • | A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Description and Operation
Navigation System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Important: 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 X2 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
