B0540
DTC B0540
CIRCUIT DESCRIPTION
The engine control module (ECM) creates the vehicle speed signal by pulsing the signal circuit to ground at a rate of 4K PPM. The instrument panel cluster (IPC) converts the 4K PPM signal to a speedometer position. The IPC also receives a class 2 message from the ECM indicating the vehicle speed. The IPC uses this class 2 message for diagnostic purposes.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B0540 Speedometer Circuit
CONDITIONS FOR RUNNING THE DTC
- The IPC receives a class 2 message from the ECM indicating that the vehicle speed is greater than 10 km/h (6 mph).
- The ignition voltage is between 9-18 volts.
CONDITIONS FOR SETTING THE DTC
- The IPC does not detect a 4K PPM signal on the vehicle speed signal circuit.
- The condition above must be present for a minimum of 5 seconds.
ACTION TAKEN WHEN THE DTC SETS
The IPC stores a DTC B0540 in memory.
CONDITIONS FOR CLEARING THE DTC
- The history DTC clears after 100 malfunction free warm-up cycles.
- The DTC becomes history when the conditions for setting the DTC are no longer present.
- The IPC receives the clear code command from the scan tool.
TEST
