Test E: The Auxiliary Audio Control Is Inoperative - Steering Wheel Controls
PINPOINT TEST E: THE AUXILIARY AUDIO CONTROL IS INOPERATIVE - STEERING WHEEL CONTROLSE1-E2:
E2-E4:
E4-E5:
E6:
Normal Operation
The audio unit sends a reference voltage to the steering wheel controls through circuit 595 (LB/RD). Each steering wheel control switch function corresponds with a specific resistance value within the switch. When a switch is pressed, the audio unit monitors the change in reference voltage to determine the requested function. Ground for the steering wheel controls is provided through circuit 57 (BK).
DTC C1976 - sets when the reference voltage on circuit 595 (LB/RD) is too high, suggesting an open circuit.
DTC C1977 - sets when the reference voltage on circuit 595 (LB/RD) is too low, suggesting a short to ground on circuit 595 (LB/RD) before the steering wheel controls, or internally shorted steering wheel controls.
DTC B2404 - sets when any fault is detected in the steering wheel controls circuit.
Possible Causes
- Circuit 57 (BK) open
- Circuit 595 (LB/RD) open or short to ground
- Clockspring
- Steering wheel controls
- Audio unit