Technical Description of OBD-II Trouble Code
The circuit range/performance of the Throttle Position Sensor/Switch “G”
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to vehicles equipped with OBD-II. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
The Throttle position sensor is a potentiometer that measures the degree of throttle opening. As the throttle is opened, the voltage reading increases.
The powertrain control module (PCM) is the primary computer that controls the vehicle. It provides a 5 Volt reference signal to the throttle position sensor (TPS) and usually a ground as well. The general measurement is as follows: at idle = 0.5 Volts; at full throttle = 4.5 Volts. If the PCM detects that the throttle angle is greater or less than it should be for a specific RPM, it will set this code. The “G” refers to a specific circuit, sensor, or area of a particular circuit.
Potential Symptoms
Symptoms that may occur with a P212B trouble code include:
Causes
A code P212B may indicate that one or more of the following has occurred:
Possible Solutions
1. If you have access to a scan tool, check the idle and WOT (wide open throttle) readings for the TPS. Verify if they are close to the mentioned specifications. If not, replace the TPS and re-check.
2. Check for an intermittent open or short in the TPS signal. To do this, an oscilliscope is required as scan tools may miss intermittent dropouts. Connect an oscilliscope and observe the signal. It should sweep up and down smoothly without any dropouts or spikes.
3. If no problems are noticed, perform a wiggle test. Wiggle the connector and harness while observing the pattern. Does it drop out? If so, replace the TPS and re-check.
4. If there is no TPS signal, check for a 5 Volt reference at the connector. If it is present, check the ground circuit for any open or shorts.
5. Ensure that the signal circuit is not at 12V. It should never have battery voltage. If it does, trace the circuit for a short to voltage and repair it.
6. Inspect the connector for any water and replace the TPS if necessary.
