Code A049: Excessive Left Front Wheel Speed Acceleration

Wheel sensors generate voltage signals as the wheel rotates. The created frequency enables the anti-lock brake controller to determine wheel RPM. If the information received is not within preset values, the anti-lock brake controller determines signal is faulty and will set Code A049. To set Code A049, the following conditions must occur.

• Brakes are not applied (brake switch off).
• Anti-lock brake controller senses illogical left front wheel speeds.

1. Observe left front wheel speed input to determine what type of input the anti-lock brake controller is sensing. Erratic or unsteady readings indicate a malfunction in wheel speed sensor. Stable readings indicate problem is intermittent.
2. Indicates wheel speed sensor has internal short to ground.
3. If resistance is infinite, wheel speed sensor has internal open condition.
4. Circuit No. 830 is connected to ground. If infinite resistance is measured, an open condition is present in circuit No. 830.
5. Circuit No. 873 is connected to ground. If infinite resistance is measured, an open condition is present in circuit No. 873.
6. All systems that can be checked have tested good. Visually inspect speed sensor, speed ring wire harness and all connectors. Check component mounting and alignment. If problem persists but source cannot be found, replace anti-lock brake controller.