P0123 - THOTTLE POSITION SENSOR/ SWITCH A CIRCUIT HIGH INPUT

The TPS sensor (Throttle Position Sensor) is located above the throttle body and is a potentiometer. Its function is to detect the angle of the throttle lever. Each time the throttle lever makes a movement, the TPS sends a signal to the Powertrain Control Module (PCM). This sensor has 3 wires which are: One reference of 5 volts, one of ground and the third is a return signal. The third cable is used by the TPS sensor to return information from the throttle position to the Power Train Control Module (PCM).

At the moment when the accelerator is closed, the signal is close to 0.45 volts. When the accelerator is depressed to the bottom (WOT) the signal voltage of the Throttle Position Sensor (TPS) is approximately 5 volts. If the PCM (Power Train Control Module) observes a voltage exceeding the permitted limit, the diagnostic code P0123 OBD2 is established.

• Check Engine service light turns on.
• At idle it can be high.

When a code P0123 OBD2 is established, it may be due to:

• There may be a short to ground or another cable of the TPS sensor (Throttle Position Sensor).
• Perhaps the Throttle Position Sensor (TPS) is not positioned correctly.
• The TPS sensor may be defective.

At the moment of solving the code P0123, you could do the following:

• In case of not presenting symptoms, the most practical thing is to erase the code and see if it reappears.
• If the motor trips or is unstable, you could inspect the cables and respective connectors that lead to the Throttle Position Sensor (TPS). Repair or replace if necessary.
• Check the voltage of the TPS sensor (Throttle Position Sensor), taking into account the factory specifications. In case the voltage is too high it can be more than 4.65 volts, with the ignition switch passed. It means that there may be a problem in the connections. Check the cables for any friction or wear. Repair or change as is appropriate.
• You can change the Throttle Position Sensor (TPS).