The accelerator pedal demand sensor provides an analogue voltage to the ECM which is proportional to the accelerator pedal position. A throttle position sensor provides a signal to the ECM which monitors throttle plate position.
After receiving these signals and monitoring the wheel speed signal output, coolant temperature, rotary switch status (automatic transmission) and inertia switch confirmation, the ECM then issues a throttle request signal. A motor within the throttle body rotates the throttle plate to a position which is relative to the position demanded.
Diagnosis and Testing
Verify the customer concern by operating the system.
Visually inspect for obvious signs of mechanical or electrical damage.
If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
If the concern is not visually evident, use a fault code reader to retrieve the fault codes before proceeding to the Symptom Chart.