The Dodge P0935 diagnostic trouble code (DTC) indicates a high voltage reading from the transmission line pressure sensor circuit. This code often appears alongside other codes, such as the P0533 (A/C refrigerant pressure sensor circuit high voltage). This article will explore the causes of the P0935 code in Dodge vehicles and offer potential solutions.
Understanding Line Pressure and the P0935 Code
Your Dodge’s transmission uses hydraulic pressure to engage gears and operate smoothly. This pressure is precisely controlled by the Transmission Control Module (TCM) via the Pressure Control Solenoid (PCS) and monitored by the Line Pressure Sensor (LPS). The LPS reports pressure readings to the TCM, ensuring optimal performance.
The P0935 code triggers when the voltage signal from the LPS exceeds 4.75 volts for more than 0.18 seconds. This high voltage signifies a problem within the line pressure sensor circuit, potentially leading to erratic shifting, harsh engagement, and transmission damage if left unresolved. The TCM adjusts line pressure based on various factors, including engine torque and driving conditions, aiming for a range between 0.35 and 4.75 volts from the LPS. During shifts or when the vehicle is in Park or Neutral, the pressure is preset between 120 and 135 PSI for consistent shift quality.
Possible Causes of P0935
Several factors can contribute to a P0935 code:
- Faulty Line Pressure Sensor (LPS): The most common culprit is a malfunctioning LPS, providing inaccurate readings to the TCM. Replacing the sensor is often the first step in diagnosis.
- Wiring Issues: Damaged or corroded wiring within the LPS circuit, especially near the connector where a resistor modification may have been performed, can cause voltage fluctuations and trigger the code. Inspecting and replacing damaged wires or connectors is crucial.
- Open or Short Circuits: An open circuit in the signal wire or a short to voltage in the sensor circuit can lead to a high voltage reading. Thoroughly checking the wiring harness for breaks or shorts is necessary.
- Sensor Ground Circuit Open: A faulty ground connection for the LPS can disrupt the voltage signal and trigger the P0935 code. Verify the integrity of the ground circuit.
- Powertrain Control Module (PCM) Issues: In rare cases, a malfunctioning PCM can contribute to the problem. However, this is less likely than other causes and should be considered after exhausting other possibilities.
Troubleshooting the P0935 Code
Diagnosing the P0935 code involves a systematic approach:
- Inspect the LPS Connector and Wiring: Visually examine the connector and wiring harness for damage, corrosion, or loose connections. If a resistor was previously installed, ensure it’s correctly wired and not causing interference. Replacing the connector and wiring related to the sensor is a good preventative measure.
- Test the LPS: Using a multimeter, test the LPS for proper resistance and voltage according to manufacturer specifications. Compare readings to the expected values to determine if the sensor is functioning correctly.
- Check for Continuity: Check for continuity in the wiring harness between the LPS and the PCM. Any breaks or shorts in the wiring should be repaired or replaced.
- Verify Ground Connection: Ensure a solid ground connection for the LPS. Clean any corrosion and tighten loose connections.
- Consult a Professional: If the problem persists, consult a qualified automotive technician with experience in diagnosing and repairing transmission issues. They can use advanced diagnostic tools to pinpoint the exact cause of the P0935 code and recommend the appropriate repairs. Further diagnostics may include checking the valve body and related components for issues that might contribute to erratic pressure readings.
Conclusion
The Dodge P0935 code signifies a potential problem within the transmission line pressure sensor circuit. While a faulty LPS is often the cause, various wiring issues, circuit problems, and even PCM malfunctions can contribute to this error. By systematically inspecting and testing the components involved, you can effectively diagnose and resolve the P0935 code, ensuring the smooth and reliable operation of your Dodge’s transmission. Ignoring this code can lead to more significant transmission damage, making timely diagnosis and repair crucial.
