Hydraulic Oil Temperature Sensor Circuit Intermittent
The Powertrain Control Module (PCM) or Transmission Control Module (TCM) detected an intermittent, erratic, or unstable voltage signal from the hydraulic oil (transmission fluid) temperature sensor circuit. This indicates the sensor's signal is dropping in and out, preventing the control module from accurately monitoring the transmission fluid temperature.
While the vehicle can usually still be driven, an intermittent temperature signal can cause the transmission to default to a fail-safe mode or shift harshly. It should be diagnosed soon to prevent potential transmission overheating or internal wear.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Harsh, erratic, or delayed transmission shifting
- Transmission locked in a fail-safe or limp mode
- Torque converter clutch fails to engage
- Transmission temperature warning light may flicker or illuminate
Likely causes
- Loose, corroded, or damaged wiring harness or connector at the temperature sensor
- Faulty hydraulic oil (transmission fluid) temperature sensor
- Low or severely degraded transmission fluid causing erratic temperature readings
- Intermittent short to ground or voltage in the sensor circuit
- Faulty Transmission Control Module (TCM) or PCM (rare)
What to check before replacing parts
Check the transmission fluid level and condition.
Look for: Low fluid or burnt, heavily contaminated fluid that could cause erratic sensor operation or actual transmission overheating.
Visually inspect the temperature sensor wiring and connectors.
Look for: Loose pins, corrosion, chafed wires, or poor connections that would cause an intermittent signal drop.
Monitor the transmission temperature sensor data via a scan tool while wiggling the harness.
Look for: Sudden spikes or drops in the temperature reading when the harness is moved, confirming a loose connection or wiring issue.
Test the sensor resistance with a digital multimeter.
Look for: Resistance values that fluctuate wildly or fall outside the manufacturer's specified range for the current ambient temperature.
Check the reference voltage and ground at the sensor connector.
Look for: A steady 5-volt reference and a solid ground; intermittent drops in voltage indicate a circuit issue between the sensor and the control module.
This page explains the generic P0941 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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