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Technical Description of OBD-II Trouble Code
High Input in Throttle Position Sensor/Switch “G” Circuit
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to vehicles equipped with OBD-II. While it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
When encountering a stored code P212D, it indicates that the powertrain control module (PCM) has detected a high voltage input from either the throttle position sensor (TPS) circuit or a specific pedal position sensor (PPS) circuit. The “G” refers to a particular circuit, sensor, or area within a circuit.
For specific information about the vehicle in question, consult a reliable source of vehicle information such as All Data DIY. This code is only used in vehicles equipped with drive by wire (DBW) systems.
The DBW system is controlled by the PCM using a throttle actuator motor, one or more pedal position sensors (also known as accelerator pedal position sensors), and multiple throttle position sensors. These sensors receive a reference voltage (typically 5 volts) and a ground. Most TPS/PPS sensors are of the potentiometer type and complete the respective circuit. The sensor contacts are actuated by a pivoting fulcrum extension on the accelerator pedal or throttle plate shaft. As the contacts move across the sensor circuit board, the sensor resistance changes, causing variations in circuit resistance and signal input voltage to the PCM.
If the signal input voltage exceeds a programmed limit for an extended period of time under certain circumstances, a code P212D will be stored and a malfunction indicator lamp (MIL) may illuminate.
Symptoms / Severity
When this code is stored, the PCM usually enters limp mode. In this mode, engine acceleration is severely limited or disabled. Symptoms of a P212D code may include:
Causes
Possible causes for this engine code include:
Diagnostic and Repair Procedures
A good starting point is to check for technical service bulletins (TSB) specific to your vehicle. There may be a known issue with a known fix provided by the manufacturer, which can save time and money during diagnosis.
To diagnose a code P212D, access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a vehicle information source like All Data (DIY) is recommended.
Begin the diagnosis by visually inspecting all system-related wiring and connectors. Also, check the throttle plate for carbon buildup or damage. Excessive carbon buildup that holds the throttle body open at startup can cause a code P212D to be stored. 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.
Next, connect the scanner to the vehicle’s diagnostic port and retrieve all stored trouble codes. Write them down in case the order in which the codes were stored becomes important. It is also helpful to keep any related freeze frame data. These notes may prove useful if the P212D code is intermittent. Clear the codes and test-drive the vehicle. If the code is reset, continue with the diagnosis.
Using the scanner data stream, voltage spikes and inconsistencies between the TPS, PPS, and the PCM can be detected. Narrow the data stream to display only relevant data for a faster response. If no spikes or inconsistencies are detected, use the DVOM to retrieve live data from each of the sensors individually. To retrieve live data with the DVOM, connect the test leads to the appropriate signal and ground circuits and 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. Voltage typically ranges from 0.5 volts at closed throttle to 4.5 volts at wide open throttle. 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.
Additional diagnostic notes:
Professional Service
While we always recommend resolving this issue mechanically, if that is not possible, we offer the option to permanently delete this specific DTC. All other codes will continue to function. If you are interested in this option, please upload your ECU file to our portal.
