P0840

Transmission Fluid Pressure Sensor/Switch A Circuit

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$17–56 (est.)

Symptoms

Incorrect gear shifting
Enabling transmission emergency mode
Check Engine light comes on
Reduced transmission efficiency
Acceleration problems

Causes

Transmission fluid pressure sensor malfunction
Open or short circuit in the sensor circuit
Poor contact in the sensor connector
Low or contaminated transmission fluid
Mechanical problems in the transmission hydraulic system

How to Fix

Check the level and condition of the transmission fluid
Inspect the connectors and wiring of the sensor
Check resistance and sensor signal
Replace transmission fluid pressure sensor if necessary
Check the transmission hydraulic system

Related codes

P0841 P0842 P0843