Input/Turbine Speed Sensor A Circuit Malfunction
P0715 indicates the PCM detected a problem with the input (turbine) speed sensor circuit in the transmission. This sensor measures transmission fluid speed and is critical for proper shift timing and transmission control. A faulty signal causes the transmission to enter limp mode with harsh shifting and poor performance.
What You Might Notice
- Transmission shifts harshly or erratically
- Check engine light illuminated
- Transmission enters limp mode with limited gear selection
- Delayed acceleration or sluggish performance
- Transmission may stay in one gear or shift incorrectly
Most Common Causes
- 1
Defective input speed sensor
The turbine speed sensor fails electronically or mechanically, sending incorrect or no signal to the PCM. This is the most common cause of P0715.
- 2
Damaged reluctor ring or shaft
The reluctor ring (tone ring) that the sensor reads becomes worn, broken, or misaligned, preventing accurate speed signal generation.
- 3
Wiring and connector damage
The sensor circuit wiring is loose, corroded, burned, or connectors are disconnected or damaged, interrupting signal transmission to the PCM.
- 4
Faulty torque converter or PCM failure
The transmission torque converter is failing or the PCM has a software error/failure, causing incorrect speed sensor interpretation.
How to Diagnose It
- 1
Check Defective input speed sensor — The turbine speed sensor fails electronically or mechanically, sending incorrect or no signal to the PCM. This is the most common cause of P0715.
- 2
Check Damaged reluctor ring or shaft — The reluctor ring (tone ring) that the sensor reads becomes worn, broken, or misaligned, preventing accurate speed signal generation.
- 3
Check Wiring and connector damage — The sensor circuit wiring is loose, corroded, burned, or connectors are disconnected or damaged, interrupting signal transmission to the PCM.
- 4
Check Faulty torque converter or PCM failure — The transmission torque converter is failing or the PCM has a software error/failure, causing incorrect speed sensor interpretation.
How to Fix It
- 1
Inspect and replace input speed sensor
Locate the input (turbine) speed sensor on the transmission, inspect the connector for corrosion or damage, and replace the sensor if faulty. Test the new sensor signal with a scan tool before reassembling.
- 2
Check and repair wiring harness
Inspect the sensor wiring harness for breaks, burns, corrosion, or loose connections. Repair or replace damaged wiring and reconnect any loose connectors securely.
- 3
Inspect transmission reluctor ring
Remove the transmission pan and inspect the reluctor ring on the turbine shaft for damage, wear, or misalignment. Replace if damaged or realign if loose.
- 4
Test and reprogram PCM if needed
Use a scan tool to verify sensor signal output while rotating the input shaft. If the sensor tests good but the code persists, the PCM may need reprogramming or replacement by a dealer.
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