Technical Description of OBD-II Trouble Code
The Throttle/Pedal Position Sensor F exhibits Maximum Stop Performance
What does this mean?
This is a standard diagnostic trouble code (DTC) for powertrain issues and is commonly found in OBD-II vehicles. This can include various vehicle brands such as Ford (e.g. F-150), Chevrolet, Dodge / Ram, Jeep, Chrysler, Kia, Toyota, VW, Ferrari, etc. While it is a generic code, the specific repair steps may differ based on the year, make, model, and powertrain configuration of the vehicle.
A stored code P2168 indicates that the powertrain control module (PCM) has detected a malfunction in the “F” throttle position sensor (TPS) or a specific pedal position sensor (PPS).
The designation “F” refers to a particular sensor or part of a circuit/sensor. For specific information about the vehicle in question, consult a reliable source of vehicle information. This code is only applicable to vehicles equipped with drive by wire (DBW) systems and is related to maximum stop or wide open throttle performance.
The DBW system is controlled by the PCM using a throttle actuator motor, multiple pedal position sensors (also known as accelerator pedal position sensors), and several throttle position sensors. These sensors are typically supplied with a 5-volt reference, a ground, and at least one signal wire.
In general, TPS/PPS sensors are of the potentiometer type. The contacts of the sensor are actuated by a mechanical extension on the accelerator pedal or the throttle plate shaft. As the contacts move across the sensor circuit board, the sensor resistance changes, resulting in variations in circuit resistance and signal input voltage to the PCM.
If the PCM detects a maximum stop/wide open throttle position sensor voltage signal (from the sensor designated F) that does not match the programmed parameter, a code P2168 will be stored and a malfunction indicator lamp (MIL) may illuminate. When this code is stored, the PCM usually enters limp-in mode, which severely limits or disables engine acceleration.
A throttle position sensor (TPS):
What is the severity of this DTC?
A P2168 should be considered severe as it can render the vehicle undriveable.
What are some of the symptoms of the code?
Symptoms of a P2168 trouble code may include:
What are some of the common causes of the code?
Possible causes for this P2168 throttle/pedal position sensor code may include:
What are some P2168 troubleshooting steps?
Refer to your vehicle information source for any relevant technical service bulletins (TSB) that match the make, model, and engine size of the vehicle in question. The symptoms and stored codes should also align. If a matching TSB is found, it can greatly assist in the diagnosis.
For a code P2168, begin the diagnosis with a visual inspection of all system-related wiring and connectors. Also, check the throttle plate for carbon buildup or damage. Clean the carbon from the throttle body according to the manufacturer’s recommendations and repair or replace any defective wiring or components as necessary. Then, retest the DBW system.
To accurately diagnose this code, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information.
Next, connect the scanner to the vehicle’s diagnostic port and retrieve all stored trouble codes. Write them down for future reference. Also, keep any related freeze frame data. These notes can be helpful, especially if the P2168 code is intermittent. Clear the codes and test-drive the vehicle to see if the code is reset.
If the code is immediately reset, use the scanner data stream to detect voltage spikes and inconsistencies between the TPS, PPS, and the PCM. Narrow down the data stream to display only relevant data for a quicker response. If no spikes or inconsistencies are detected, use the DVOM to retrieve live data from each of the sensor signal wires. Connect the positive test lead to the appropriate signal wire and the ground test lead to the ground circuit, then observe the DVOM display while operating the DBW. Look for voltage spikes as the throttle is slowly actuated from the closed position to wide open throttle. The voltage usually ranges from 0.5 volts at closed throttle to 4.5 volts at wide open throttle, but consult your vehicle information source for exact specifications. If spikes or other irregularities are detected, suspect that the sensor being tested is defective. An oscilloscope is also a useful tool for testing sensor operation.
If the sensor is functioning as intended, disconnect any related controllers and test individual circuits with the DVOM. System wiring diagrams and connector pinout charts can help identify which circuits to test and where to locate them on the vehicle. Repair or replace system circuits as needed.
Suspect a defective PCM or a PCM programming error only if all system sensors and circuits check out.
Some manufacturers may require replacing the throttle body, throttle actuator motor, and all throttle position sensors as a single unit.
