Error Code P083C is defined as Transmission Fluid Pressure Sensor / Switch G Circuit Low. Error Code P083C is a generic trouble code, meaning it applies to all vehicles with the OBD-II system, especially those made from 1996 up to present. This includes vehicles from, but not limited to, Acura, Chevrolet, Honda, Saturn, Jeep, and Toyota. Specifications on the definition, troubleshooting, and repairs, of course, vary between make, model, and powertrain configuration.
The Transmission Fluid Pressure Sensor Switch (TFPS) is usually attached to the side of the valve body inside the transmission. In other cases, it is screwed into the side of the transmission case or the body itself.
The TFPS works by converting mechanical transmission pressure, an electrical signal for the Powertrain Control Module (PCM) or the Transmission Control Module (TCM). In most cases, the PCM/TCM informs other controllers using the vehicle’s data communication bus.
To determine the transmission operating pressure or when a shift is taking place, the PCM and TCM receives voltage signal. This error code is stored if the “G” input doesn’t match with the normal operating voltages stored in the memory of PCM/TCM. It could also be caused by an internal mechanical issue inside the transmission. To determine which “G” circuit is applicable for your vehicle, you can refer to the specific repair manual.
Error Code P083C is usually an electrical circuit error (TFPS sensor circuit) problem. This can’t be overlooked in the troubleshooting stage, especially if it’s an intermittent issue.
Diagnosis and repair for this code may depend on the manufacturer, TFPS type sensor, and wire colors.
Other related transmission fluid pressure sensor “G” circuit includes:
This code activates the Check Engine light. Other noticeable symptoms include:
- Vehicle starts in either 2nd gear or 3rd gear (limp mode)
- Change in shift quality
- Short to ground in the signal circuit to the TFPS sensor
- Damaged TFPS sensor (internally short)
- Defective PCM (programming issue after replacement)
How to Check
Start your diagnosis with a technical service bulletin (TSB), based on the specific year, make, model, engine size, symptoms, and power plant of the vehicle (if applicable). This can save a lot of time in the long run.
Some good examples are if there are other known power-related codes set along with the Error Code P038A, or if there is more than one pressure sensor/switch code set. If there is, you can start the diagnosis with either the power-related error code or the multiple code diagnosis. These may be the reason for the code.
Next, find the TFPS in your vehicle. It’s usually attached to the side of the valve body inside the transmission, or screwed into the side of the transmission case or body itself. Inspect the connectors and wirings, look for signs of damage and wear and tear, such as rubbing, scraping, burn spots, bare wires, or melted plastics. Pull the connector apart and check the metal parts of the terminals inside the connectors. If they are burnt or with green tint (corrosion, especially if attached outside the transmission case), then they should be repair or replaced. You can use an electrical contact cleaner and a plastic bristle brush to clean the terminals. Let them dry and apply electrical grease where the terminals contact.
Using a scan tool, clear the diagnostic trouble codes from memory and see if the code comes back. If it doesn’t come back, then the connector is likely the problem. This is the most common concern of this code, as the external transmission connections are prone to corrosion.
If the code comes back, test the TFPS sensor and all the associated circuits. With Key Off, disconnect the electrical connector at the TFPS sensor. Then, connect the black lead of your DVOM (digital volt ohmmeter) to the ground or low reference terminal at the TFPS sensor wiring harness connector. Connect the red lead end of the DVOM to the signal terminal of the TFPS sensor wiring harness connector. Then, turn to Key On, Engine Off. Check the specifications set by the manufacturer. The voltmeter should read either 5V or 12V. Wiggle the connections and see if the numbers change. If the voltage is incorrect, then you need to either repair power or ground wire or replace the PCM/TCM.
If your vehicle was able to pass the prior test, test one lead of the ohmmeter to the signal terminal at the TFPs sensor and the other end to the ground or low reference terminal. Check the specifications set by the manufacturer on the resistance of the sensor to test the resistance to pressure when there is no pressure applied to it. Again, wiggle the connector at the TFPS while monitoring the resistance. If the ohmmeter failed, then your fault is in the TFPS, and it must be replaced.
If your vehicle passes all tests above and continues to show the Error Code, you may have a failed TFPS sensor. Defective PCM/TCM can be the cause of the problem, too, as well as an internal transmission malfunction. If you’re not sure what to do, it’s best to ask assistance from a certified automotive diagnostician.
To install correctly, PCM/TCM must be programmed and calibrated to the vehicle.
How to Fix
- Repair or replacement of faulty or damaged wires in the TFPS
- Cleaning TFPS connectors off corrosion
- Repair or replacement of faulty TFPS sensor
- Replacement of PCM/TCM
The severity of this Error Code depends on which circuit the failure occurred. Since it’s an electrical failure, the PCM/TCM can compensate (to some degree). If electronically controlled, a failure could mean the PCM/TCM modifies the shifting of the transmission.