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DTC P2123: Accelerator Pedal Position Sensor No. 1 Circuit High Input: Notes

WARNING: This page is about a different car, the 2004 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: DTC P2123: Detection Condition & Possible Causes Chart
G00974522Courtesy of MAZDA MOTORS CORP.