Fix codes P2122 P2123 P2125 P2127 P2128 Hyundai Sante Fe
All these trouble codes relate to problems with the accelerator pedal position (APP) sensor. To test, unplug the electrical connector at the accelerator pedal position sensor. Using a digital multimeter and with the key in the RUN position, check the Green wire for 5 volts (pos lead from meter to green wire, neg lead to ground). Then check the black/white wire for good ground (pos lead from meter on Green wire, neg lead to black/white wire)–should read 5 volts.
Reconnect electrical connector to sensor. Pierce or back-probe the wires to get the following voltage readings with the key in the RUN position: Connect positive lead from meter to the white wire (neg lead to ground). You should see 0.3-0.8 volts with your foot OFF the pedal. Monitor that voltage for while without touching anything else. It should stay steady. Wiggle the connector and the wiring harness. It should stay steady. If the reading is less than 0.3 volts, the sensor is bad. If the voltage changes as you wiggle the connector or the harness, the wiring is bad. If you see the correct voltage range with foot off the pedal, then slowly press pedal down. Voltage should rise to 4-5 volts with foot all the way to the floor.
© 2012 Rick Muscoplat