# P0715: Input/Turbine Speed Sensor "A" Circuit **Verdict:** Drive to a shop this week Transmission - Generic OBD-II code, applies to all gasoline cars and light trucks sold in the US since 1996. - **Typical cost:** $150-$700 - **Urgency:** This week - **Most likely:** Failed input speed sensor or wiring - **DIY?:** Shop job on most cars ## Quick answer P0715 means the transmission computer is not getting a proper signal from the input (turbine) speed sensor, which measures how fast the transmission's input shaft is spinning. Without it, the computer cannot judge shifts correctly, so you may get harsh shifts or a transmission stuck in one gear. A failed sensor or wiring problem is the usual cause. ## What does P0715 mean? In an automatic transmission, the torque converter's turbine drives the transmission's input shaft. The input or turbine speed sensor reads a toothed wheel or drum turning with that shaft and sends the transmission computer a pulse signal that speeds up as the shaft spins faster. The computer compares input speed with output speed and engine RPM to judge gear ratio, shift timing, and torque converter slip. P0715 sets when the input speed signal is missing, erratic, or out of range while the transmission is in gear and the vehicle is moving, so the computer cannot trust it. "Circuit" means the problem can be anywhere in the sensor, its wiring and connector, or the computer's input, not only the sensor itself. Sensor "A" is the first of possibly several input sensors. Many transmissions go into limp mode as soon as this code sets. ## What are the symptoms of P0715? - Harsh or erratic shifting - Transmission stuck in one gear (limp mode) - Speedometer problems on some vehicles - Check engine light on, sometimes with P0700 ## What causes P0715? Ranked from most to least likely. Check them in this order: the cheap, common causes first. 1. **Failed input/turbine speed sensor** (most common). Input speed sensors live in or on a hot transmission case and can fail internally after years of heat cycles. Because many are magnetic, fine metal particles from normal wear also collect on the tip and weaken the signal. A missing or erratic input speed reading on a scan tool, while engine RPM is steady, points to the sensor. 2. **Damaged wiring or connector** (common). The sensor connector and wiring sit on or near the transmission, often close to the exhaust, where heat, vibration, and fluid leaks take a toll. Corroded or bent pins, an oil-soaked connector, or a chafed wire can drop the signal, sometimes only over bumps or when hot. A wiggle test with the engine running can reveal it. 3. **Low or contaminated transmission fluid** (less common). Debris suspended in old or contaminated fluid can collect on magnetic sensors, especially internal ones, and blur the signal. Very low fluid can also cause slipping that makes speed readings look wrong to the computer. Dark, burnt fluid or heavy debris on the sensor tip suggests the transmission needs further checks as well. 4. **Damaged reluctor (tone) wheel** (rare). The sensor reads teeth or slots on a rotating drum or wheel inside the transmission. If those teeth are damaged, or the drum is worn or cracked, the sensor sees an incomplete pattern even though it works. This is rare and is usually found only when the transmission is opened up, often alongside other signs of internal wear. 5. **Transmission computer fault** (rare). A failed input circuit inside the transmission computer, or a poor computer power or ground connection, can make a good sensor signal look missing. This is rare, and a shop checks it only after the sensor and wiring test good. The shop may also check whether the maker has released a software update for the module. ## How do you diagnose P0715? 1. Read all transmission codes and check freeze-frame data. 2. Watch input speed on a scan tool while driving, comparing it with engine RPM and output speed. 3. Inspect the sensor connector and wiring for damage, oil, or corrosion. 4. Measure sensor resistance or check its signal with a scope, following your vehicle's specs. ## How do you fix P0715, and what does it cost? | Fix | Typical cost | What it involves | | --- | --- | --- | | Replace input speed sensor (external) | $150-$400 | Many sensors bolt into the outside of the transmission case. | | Replace input speed sensor (internal) | $300-$700 | Some sensors are inside the transmission pan or valve body and need more labor and fresh fluid. | | Repair wiring or connector | $100-$300 | Fixes corroded pins or damaged wires. | ## Is it safe to drive with P0715? > **Drive to a shop this week.** You can usually drive carefully to a shop, but limp mode limits you to one gear and harsh shifts can stress the transmission. Avoid highways if the car will not upshift. ## Will P0715 fail an emissions test? P0715 makes the engine computer turn on the check engine light, often along with P0700, so the car fails an OBD-II emissions test in most states. Clearing the codes resets the readiness monitors as well. Repair the sensor or wiring first, then drive normally for several days so the monitors finish before the test. ## After the repair: clearing P0715 After the repair, clear transmission and engine codes and test drive through all gears. A scan tool should show a smooth input speed reading that tracks engine RPM in each gear. Some transmissions need an adaptive relearn after sensor or fluid work. Normal shifts, no limp mode, and no returning code mean the fix worked. ## How to prevent P0715 - Change transmission fluid on schedule to limit metal particles that stick to magnetic speed sensors. - Fix transmission fluid leaks quickly so oil does not seep into sensor connectors. - Make sure wiring clips go back in place after exhaust or transmission work so wires stay clear of heat. - Use the exact fluid type your transmission specifies instead of generic fluids or additives. - Have harsh or erratic shifts checked early, before limp mode or extra wear sets in. ## Codes often seen with P0715 - [P0700](/codes/p0700): Transmission Control System (MIL Request) - [P0730](/codes/p0730): Incorrect Gear Ratio - [P0500](/codes/p0500): Vehicle Speed Sensor "A" - [P0741](/codes/p0741): Torque Converter Clutch Solenoid Circuit Performance/Stuck Off ## Frequently asked questions ### Can I drive with a P0715 code? You can drive carefully for a short distance, but the transmission may stay in one gear and shift harshly. Avoid highways if it will not upshift, because the engine will rev high at speed. Get it checked soon to avoid extra wear on the clutches and torque converter. ### What does the input speed sensor do? It tells the transmission computer how fast the transmission's input shaft is turning, which is driven by the torque converter. The computer compares that with output speed and engine RPM to control shift timing, shift feel, and torque converter lockup. Without it, the computer falls back to a protective mode. ### Is P0715 a sign my transmission is failing? Usually not, because the most common cause is the sensor or its wiring. If heavy metal debris is found on the sensor or in the pan, or P0730 shows up too, the shop may recommend checking the transmission further. A clean sensor tip and healthy fluid are good signs. ### How much does it cost to fix P0715? Most P0715 repairs cost $150 to $700. An external sensor that bolts into the transmission case usually runs $150 to $400, while an internal sensor inside the pan or on the valve body costs about $300 to $700 because of the extra labor and fresh fluid. Wiring repairs run $100 to $300. ### Where is the input speed sensor located? It depends on the transmission. On many, it bolts into the outside of the case, often toward the front near the bell housing, while on others it sits inside the pan or on the valve body. Your vehicle's service manual or a parts catalog shows the exact location for your model. ### Can I replace the input speed sensor myself? Sometimes, if your sensor bolts into the outside of the case and you can reach it. Internal sensors mean dropping the pan, replacing fluid, and refilling to the correct level, which many newer cars make hard without a lift and scan tool. Confirm the wiring is good before buying a sensor. ### What is the difference between P0715 and P0720? P0715 points to the input or turbine speed sensor, which measures speed going into the transmission. P0720 points to the output speed sensor, which measures speed leaving it. Both can cause harsh shifts or limp mode, but they are different parts in different places, so the code tells you which to test. ### Why does P0715 put my car in limp mode? Without a trustworthy input speed signal, the transmission computer cannot judge gear ratios or shift quality, and a badly timed shift could damage clutches. To protect the transmission, many computers lock it in one gear until the fault is fixed. Restarting may restore normal shifting briefly until the fault returns. ### Will P0715 fail an emissions test? Yes, in most OBD-II testing states. P0715 makes the engine computer turn on the check engine light, and a lit light with a stored code is a fail. Clearing the code also resets the readiness monitors, so repair the sensor first and drive normally for several days before the test. ### Can low transmission fluid cause P0715? It can contribute, but it is not the usual cause. Low fluid can cause slipping that makes speed readings look wrong, and debris in old fluid can coat a magnetic sensor. Checking fluid level and condition early is cheap, and it affects whatever repair comes next. ## Sources - [SAE J2012: Diagnostic Trouble Code Definitions](https://www.sae.org/standards/content/j2012_201812/) ## Other transmission codes - [P0700 Transmission Control System (MIL Request)](https://diagxcar.com/codes/p0700) - [P0705 Transmission Range Sensor "A" Circuit (PRNDL Input)](https://diagxcar.com/codes/p0705) - [P0717 Input/Turbine Speed Sensor "A" Circuit No Signal](https://diagxcar.com/codes/p0717) - [P0720 Output Shaft Speed Sensor "A" Circuit](https://diagxcar.com/codes/p0720) - [P0730 Incorrect Gear Ratio](https://diagxcar.com/codes/p0730) - [P0731 Gear 1 Incorrect Ratio](https://diagxcar.com/codes/p0731) - [P0732 Gear 2 Incorrect Ratio](https://diagxcar.com/codes/p0732) - [P0740 Torque Converter Clutch Solenoid Circuit/Open](https://diagxcar.com/codes/p0740) - [P0741 Torque Converter Clutch Solenoid Circuit Performance/Stuck Off](https://diagxcar.com/codes/p0741) - [P0750 Shift Solenoid "A"](https://diagxcar.com/codes/p0750) - [P0500 Vehicle Speed Sensor "A"](https://diagxcar.com/codes/p0500) ## Symptoms - [Why won't my car go into gear?](https://diagxcar.com/symptoms/car-wont-go-into-gear) ## Repair costs - [Transmission replacement cost](https://diagxcar.com/cost/transmission-replacement) --- Source page: https://diagxcar.com/codes/p0715 Updated: 2026-11-03 General information, not a substitute for a qualified mechanic.