What it means
The transmission fluid pressure sensor/switch G circuit signal is below the expected level.
At a glance
- Usually lights the check-engine light
How it works
Transmission pressure sensor/switch G monitors pressure-related conditions in a transmission circuit that this code does not identify. The transmission control module sets this code when the G circuit signal falls below the expected level, which can result from a short to ground or a connection fault.
Common causes
Most likely first.
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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
How to diagnose it
- Save freeze-frame data and examine sensor/switch G live data alongside shift behavior and related transmission codes.
- Inspect the G sensor connector and harness for chafing, exposed wire, fluid contamination, corrosion, or loose terminals.
- With the circuit isolated according to the manufacturer's procedure, check the signal wire for a short to ground and test connector continuity.
- Check the sensor's reference and ground circuits as applicable, using the wiring diagram and manufacturer's specification to locate a circuit fault.
- If the wiring and supply circuits are correct, test pressure sensor/switch G and investigate actual transmission pressure only as directed by the manufacturer.
Common fixes
- Repair a signal wire shorted to ground or chafed through its insulation.
- Clean and secure the G sensor connector, repairing corroded or loose terminals.
- Repair a fault in the sensor's reference or ground circuit.
- Replace pressure sensor/switch G if it fails the specified test.
Can I keep driving?
Limit driving if shifting becomes harsh, delayed, or slipping, and stop if the transmission cannot engage gears reliably. Continued operation with a low pressure signal or an underlying pressure problem may worsen transmission damage.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.