P0940
Hydraulic Oil Temperature Sensor Circuit High
The hydraulic oil temperature sensor reports a circuit high fault. Oil temperature feedback for hydraulic system is unreliable.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: easy
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- Signal wire shorted to B+Common
- Open sensorPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Hydraulic Oil Temp Sensor
- Wiring Harness
- TCM
P0940 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.