P0938 Fault Code

Hydraulic Oil Temperature Sensor Range/Performance

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0938 fault code indicates an issue with the Hydraulic Oil Temperature Sensor, specifically relating to its range or performance. This sensor is critical in monitoring the temperature of the hydraulic oil within the vehicle's transmission system. If the sensor detects temperatures outside the expected range, it triggers this fault code, potentially leading to Transmission Performance issues.

What are the symptoms of the P0938 code?

Symptoms associated with a P0938 fault code may include:

• Transmission overheating leading to erratic performance
• Poor shifting quality, including slipping or harsh shifting
• Check Engine Light illumination on the dashboard
• Abnormal smells from the transmission fluid due to overheating
• Possible transmission failure if not addressed promptly

What causes the P0938 code?

Common causes of a P0938 fault code include:

• A defective or faulty hydraulic oil temperature sensor
• Wiring issues such as short circuits or open circuits in the sensor harness
• Contaminated or degraded hydraulic oil affecting sensor readings
• Transmission fluid level being low or incorrect
• Malfunctioning transmission control module (TCM)

How to fix P0938?

To resolve a P0938 fault code, follow these steps:

1. Use a diagnostic scanner to confirm the fault code and check for any related codes.
2. Inspect the hydraulic oil temperature sensor for any signs of damage or corrosion.
3. Check the wiring and connectors for continuity and integrity; repair or replace as needed.
4. Verify the condition and level of the hydraulic oil; change if it is dirty or low.
5. If the sensor and wiring are in good condition, test and potentially replace the transmission control module if it is determined to be faulty.