Input/Turbine Speed Sensor Circuit Malfunction
What does this mean?
Code P0715 indicates the PCM/TCM is not receiving a proper signal from the input/turbine speed sensor in the transmission.
Disclaimer: This diagnostic code is part of the standard OBD2 system and can apply to Audi Q8 models manufactured from 1996 to 2026. However, please note that the presence of this specific code depends on your vehicle's exact engine configuration, options, and production year.
Common Causes
Faulty input/turbine speed sensor
Low, dirty, or burnt transmission fluid
Damaged, chafed, or broken wiring harness
Corroded or loose electrical connector
Symptoms to Watch For
- Check Engine Light is illuminated
- Transmission slipping between gears
- Hard or harsh gear shifting
- Transmission stuck in one gear
- Vehicle enters reduced power / limp mode
How to Diagnose
Common Solutions
**Replace the Input/Turbine Speed Sensor:** This is the most frequent solution if electrical tests confirm the sensor itself is faulty (e.g., incorrect resistance, no signal output, or erratic waveform).
**Repair or Replace Damaged Wiring/Connector:** If the visual inspection or electrical tests identify damaged wiring, corroded terminals, or a faulty connector, repairing the specific section of the harness or replacing the connector will resolve the circuit malfunction.
**Clean Debris from Sensor Tip/Reluctor Wheel:** In some instances, metallic shavings or sludge can accumulate on the magnetic tip of the sensor or on the reluctor wheel, obstructing the sensor's ability to read rotational speed. Removing the sensor and carefully cleaning both the sensor tip and the accessible portion of the reluctor wheel can restore proper function.
**Replace the Transmission Control Module (TCM) or Powertrain Control Module (PCM):** This is a less common but possible fix if all sensor and wiring tests pass conclusively, and the control module is confirmed to be failing to provide proper reference voltage, ground, or to correctly process the sensor's input signal. This should only be pursued after thoroughly ruling out all other possibilities.