P2138 - THROTTLE / PEDAL POSITION SENSOR / SWITCH D / E VOLTAGE CORRELATION

The electronic throttle control is a system composed of the Throttle Position Sensor (TPS), a throttle body electronically controlled by an internal motor, two throttle position sensors used for correlation factors, and the engine management module.

When the accelerator pedal is depressed, a sensor indicates the desired amount of throttle opening. That information is sent to the Powertrain Control Module (PCM). In response, the PCM sends a voltage to the electric motor, which opens the throttle plate. Besides, two-position sensors are located in the throttle body, which converts the amount of throttle opening into a voltage signal.

The PCM constantly observes the correlation between the two voltages. When the voltages match, the system operates correctly. But if there is a difference in the voltages for a few seconds, the DTC P2138 OBDII code is set.

• Check Engine light ON.
• The vehicle may fail to start.
• Motor stalling.
• Deficiencies during acceleration.
• Sudden loss of power.

Reasons for setting the P2138 OBD2 trouble code are:

• Deficiencies in electrical connections due to bad throttle body wiring or connectors.
• The throttle body gears do not rotate properly due to damage to the top cover.
• Defects in the throttle body.
• The Throttle Position Sensor may be damaged.

To solve the P2138 OBDII diagnostic code, take into account these suggestions:

• Check if the Technical Service Bulletins have the solution for this code.
• Check the connector and its terminals. Make sure they are not corroded. Repair as needed.
• Inspect the throttle body and pay attention to the top cover. If you find defects with the cover you should replace it. Replace the throttle body if necessary.
• Replace the Throttle Position Sensor.