P0715
Input/Turbine Speed Sensor A Circuit
If your code reader dashboard displays the generic DTC error code P0715, your vehicle is currently experiencing an active failure related to "Input/Turbine Speed Sensor A Circuit". Proper system troubleshooting is required to safely clear this warning.
Driver's Summary
P0715 is triggered when the PCM detects an abnormal condition associated with input/turbine speed sensor a circuit. The most common signs are harsh shifting, transmission slips, speedometer drops to zero. This is a serious fault — avoid extended driving and have your vehicle inspected by a mechanic as soon as possible to prevent further damage.
Symptoms
Harsh shifting, transmission slips, speedometer drops to zero
Common Causes
- Faulty input speed sensor
- Dirty transmission fluid
- Damaged sensor wiring harness
- Failed transmission control module (TCM)
How to Fix
- 1 Replace transmission input speed sensor
- 2 Perform transmission fluid flush
- 3 Repair wiring to sensor
- 4 Scan and test TCM
Technical Explanation
P0715 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. The TCM also cross-references engine torque demand, throttle position, and vehicle speed to determine whether the actual gear ratio deviation is genuinely abnormal or a result of expected torque converter slip during aggressive acceleration. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
Driving with an active P0715 fault risks accelerating damage to faulty input speed sensor and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
The most common mistake with P0715 is replacing the sensor without verifying the reference voltage and ground integrity first. Use a scan tool to monitor the sensor's live output; a truly failed sensor shows a stuck, flatlined reading — a sensor that fluctuates but reads slightly off usually indicates a wiring or vacuum issue, not a dead sensor. Always spray electrical contact cleaner on the connector pins before condemning the sensor.
Speed sensor: $150 - $300; Fluid flush: $150 - $250