P077A

Output Shaft Speed Sensor Circuit - Loss of Direction Signal

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$17–56 (est.)

Symptoms

Incorrect gear shifting
Check engine light comes on
Switching to emergency mode of the gearbox
Power Loss
Jerks when shifting gears

Causes

Output shaft speed sensor malfunction
Open or short circuit in the sensor circuit
Damage to the sensor connector
Problems with the transmission control unit
Mechanical damage to the output shaft

How to Fix

Check the condition of the output shaft speed sensor
Check the integrity of the sensor circuit and connectors
Check sensor resistance
Check the sensor signal with an oscilloscope
Replace sensor if necessary

Related codes

P077B P077C P077D