DTC 2123

^ Full throttle switch (circuit voltage always high). The full throttle switch has battery power at one terminal whenever the ignition is turned on (from fuse #28). If the throttle is in the wide open position, the switch is closed and conducts battery power to terminal #31 of the fuel control unit and terminal #9 of the ignition control unit. The control units measure the voltage at their respective terminals. Battery power at these terminals indicate to the ECUs that the throttle is in the wide open position (full throttle switch closed), while no power (circuit voltage low) indicates the throttle is not fully open. When this code is present, it means that one of the control units has detected both a full throttle signal, and an idle signal at the same time. This cannot occur unless at least one of the signals is false.

This code may be caused by:

a. Faulty full throttle switch (always closed).
b. Circuit shorted to battery power, between full throttle switch and terminal #31 of fuel control unit, or between terminal #31 of fuel control unit and terminal #9 of ignition control unit.
c. Fault in idle switch circuit (see code 2121).