Hydraulic Oil Temperature Sensor Range/Performance
The P0938 code indicates that the Powertrain Control Module (PCM) has detected a signal from the hydraulic oil temperature sensor that is outside the expected range or not performing correctly. This sensor monitors the temperature of the hydraulic fluid in the transmission or clutch system, and the PCM uses this data to adjust shift patterns and line pressure. A faulty sensor, wiring issues, or low hydraulic fluid can cause this code.
01. Most Common Causes
- Faulty hydraulic oil temperature sensor
- Damaged or corroded wiring/connectors to the sensor
- Low or contaminated hydraulic fluid
- Internal transmission or clutch system issues
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission slipping or overheating
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and check freeze frame data.
Step 2: Inspect the hydraulic oil temperature sensor and its wiring for damage or corrosion.
Step 3: Check hydraulic fluid level and condition; top off or replace if necessary.
Step 4: Test sensor resistance and compare to manufacturer specifications.
Step 5: If sensor and wiring are okay, perform a transmission system test to rule out internal issues.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can lead to transmission damage. You may experience shifting problems and overheating.
How much does it cost to fix?▼
Typically $50-$150 for sensor replacement, but could be higher if wiring repairs or transmission service is needed.