Circuit Description
The navigation radio receives the vehicle speed signal from the engine control module (ECM) through a dedicated circuit shared with the instrument cluster.
DTC Descriptor
The diagnostic procedure supports the following DTCs:
DTC B0000 Vehicle Speed Information Circuit
The vehicle has DTCs including the DTC symptoms. Refer to DTC Symptom Descriptionfor DTC information.
DTC Symptom | DTC Symptom Description |
|---|---|
5A | Malfunction |
Conditions for Running the DTC
| • | The navigation radio must detect a power mode transition to ON. |
| • | The radio does not set this DTC if B 1327 or B 1328 is current. |
| • | The vehicle speed must be greater than 15 km/h continuously for 10 seconds 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 speed is greater than 15 km/h for 10 seconds, 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. |
Diagnostic Aids
The following conditions may cause an intermittent malfunction:
| • | Wiring Fault |
| • | Wire insulation which is rubbed through |
| • | Wiring broken inside the insulation |
| • | A loose connector pin |
Test Description
The following numbers are corresponding to the steps in the diagnostic table.
-
This step determines if the fault is present.
-
This step tests for an open in the vehicle speed signal circuit between the IPC and the navigation radio. A shorted circuit may cause a fault in the IPC or navigation radio.
Step | Operation | Yes | No |
|---|---|---|---|
Schematic Reference: Radio/Navigation System Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 | This step tests for an open in the vehicle speed signal circuit between the ECM and the navigation radio. Refer to Wiring Repairs and Circuit Testing. Did you find and correct the condition? | Go to Step 5 | Go to Step 3 |
3 | Inspect for poor connections at the harness connector of the navigation radio. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 5 | Go to Step 4 |
4 | Replace the navigation radio. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Is the replacement complete? | Go to Step 5 | -- |
5 |
Does the DTC set again? | Go to Step 2 | System is OK |
