P0843
Transmission Fluid Pressure Sensor/Switch A Circuit High
The transmission fluid pressure sensor A circuit reports voltage above threshold, indicating short to power or open ground.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
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 shorted to batteryCommon
- Open ground referencePossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Transmission Fluid Pressure Sensor
- Wiring Harness
P0843 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.