B0940

Coolant Level Sensor Circuit Open

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$22–56 (est.)

Symptoms

Coolant level warning light comes on
Incorrect coolant level readings on the dashboard
Possible engine overheating

Causes

Broken or damaged sensor wiring harness
Oxidation of sensor contacts
Coolant level sensor malfunction
Problems with the on-board computer

How to Fix

Check the coolant level in the expansion tank
Inspect the wiring harness and sensor contacts for damage and oxidation.
Check the resistance of the coolant level sensor (compare with factory values)
If necessary, replace the sensor or repair the wiring harness
Reset the error and check if it returns

Related codes

P0115 P0116 P0117