Speedometer Malfunction: Description

The meter CPU receives vehicle speed signals from the brake actuator assembly (skid control ECU) via the CAN communication system. The speed sensor detects the wheel speed and sends the appropriate signals to the brake actuator assembly (skid control ECU). The brake actuator assembly (skid control ECU) supplies power to the vehicle speed sensor. The brake actuator assembly (skid control ECU) detects vehicle speed signals based on the pulses of the voltage.

HINT: 

• Factors that affect the indicated vehicle speed include tire size, tire inflation, and tire wear. The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, see the reference chart See step  1.
• If the vehicle speed sensor circuit has a malfunction, the brake actuator assembly (skid control ECU) stores the DTCs. Troubleshoot the Brake Control System. Refer to DTC C1401: Front Speed Sensor RH Malfunction; DTC C1271: Low Output Signal of Front Speed Sensor RH (Test Mode DTC); DTC C1272: Low Output Signal of Front Speed Sensor LH (Test Mode DTC); DTC C1402: Front Speed Sensor LH Malfunction .