OBD Guide

P077A

Output Shaft Speed Sensor Circuit - Loss of Direction Signal

P077A is an OBD-II diagnostic trouble code meaning: Output Shaft Speed Sensor Circuit - Loss of Direction Signal. Common causes: output shaft speed sensor malfunction, open or short circuit in the sensor circuit. Estimated repair cost: $17–56.

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

  1. Check the condition of the output shaft speed sensor
  2. Check the integrity of the sensor circuit and connectors
  3. Check sensor resistance
  4. Check the sensor signal with an oscilloscope
  5. Replace sensor if necessary

Related codes

Error P077A by Vehicle Brand

FAQ

What does the P077A code mean?

P077A is an OBD-II diagnostic trouble code that indicates: Output Shaft Speed Sensor Circuit - Loss of Direction Signal

What causes a P077A error code?

The most common causes of P077A include: Output shaft speed sensor malfunction; Open or short circuit in the sensor circuit; Damage to the sensor connector; Problems with the transmission control unit.

How do I fix a P077A diagnostic trouble code?

To fix P077A: Check the condition of the output shaft speed sensor. Check the integrity of the sensor circuit and connectors. Check sensor resistance. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P077A?

Limited driving only, diagnose soon

How much does it cost to fix P077A?

The estimated repair cost for P077A is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat