P0715 Code: Input/Turbine Speed Sensor A Circuit
The transmission computer has lost a reliable input-shaft speed signal, so shifts get harsh or it goes limp.
At a glance
Severity: Moderate
- Meaning
- Input/Turbine Speed Sensor A Circuit
- System
- Transmission · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $100–$2,500
- DIY difficulty
- Moderate
The input or turbine speed sensor (ISS/TSS) counts how fast the torque converter turbine – and with it the transmission input shaft – is turning. The module compares that speed with engine rpm to measure converter slip, and with output shaft speed to confirm which gear is actually engaged and how quickly a clutch applies during a shift. P0715 is the general circuit code: the module has detected an electrical fault in the sensor circuit, such as an open, a short or a supply problem. Without input speed the module can't control shift pressure precisely, so most transmissions switch to a firm fallback program or limp mode. The sensor is often bolted into the case and replaceable from outside, but on some designs it sits inside the transmission or in the control unit.
Can I keep driving? The car usually drives, but often only in a fixed gear or with hard shifts. Keep speeds moderate, avoid towing and hard acceleration, and get it diagnosed soon – driving long distances in limp mode heats the fluid and wears clutches.
How to read P0715
- P Powertrain
- 0 Generic (SAE)
- 7 Transmission
- 15 Specific fault
Symptoms
- Harsh, banging or erratic upshifts and downshifts
- Transmission stuck in one gear (limp mode), often 2nd or 3rd
- Engine rpm flares between shifts
- Torque converter no longer locks up
- Speedometer usually keeps working (it uses a different sensor)
- Check engine light, commonly with P0700
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Failed input/turbine speed sensor
- Damaged wiring or corroded connector at the sensor
- Metal debris stuck to the sensor's magnetic tip
- Sensor integrated in the internal harness, conductor plate or mechatronic failed
- Lost supply voltage or ground for a Hall-type sensor
- Transmission module fault
Diagnosis step by step
Read input speed at idle
With the engine idling in Park or Neutral, the input or turbine speed on many transmissions reads close to engine rpm; with Drive selected and your foot hard on the brake it drops to zero. A value stuck at zero, jumping wildly or missing entirely confirms the circuit problem.
Tools: OBD-II scanner
Locate and inspect the sensor
Find the input speed sensor on the transmission case – often on top or the front face near the bell housing. Check the connector lock, look for oil or water in the plug and broken wires along the harness.
Tools: Flashlight, Screwdriver
Test the sensor according to its type
A two-wire magnetic sensor should typically measure a few hundred to around 1,500 ohms and produce a rising AC voltage as it turns. A three-wire Hall sensor needs its supply (often 5 V or 12 V) and ground at the connector; its signal can only be checked while running.
Tools: Multimeter
Pull the sensor and check the tip
Remove the retaining bolt and pull the sensor out. A furry coating of metal particles on the magnet weakens the signal – clean it, but note that heavy debris means internal wear and warrants a closer look at the fluid.
Tools: Screwdriver, Towels & shallow pan
Refit, clear and road-test
Install the sensor with a new O-ring, tighten the bolt to spec, and clear the codes. On a road test, input speed should track engine rpm smoothly and fall into a fixed ratio with output speed in each gear.
Tools: Torque wrench, OBD-II scanner
Where the parts are
- 1Battery
- 2Alternator
- 3Engine computer (ECM)
- 4CAN bus
- 5Transmission
- 6Wheel speed sensor
- 7High-voltage battery
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Repair connector or wiring to the input sensor | No | $100–$300 |
| Replace external input/turbine speed sensor | Yes | $150–$380 |
| Replace internal sensor (pan or valve body removal) | No | $400–$1,000 |
| Replace mechatronic unit or conductor plate with integrated sensors | No | $900–$2,500 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Hyundai
Many Hyundai and Kia four- and five-speed automatics use external speed sensors called PG-A (input) and PG-B (output) in service information. Input sensor codes on these models are frequently cured by a new sensor or a cleaned connector, and the sensor is reachable from outside the case.
Nissan
Nissan conventional automatics and CVTs report input sensor faults as P0715 or P0717; on CVTs the input sensor is also called the primary speed sensor. Check the connector and the fluid condition before condemning the whole transmission.
Field data
| Ford | 10 | F-150 SUPERCAB, Edge, Expedition |
|---|
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Will fail
P0715 sets the check engine light, so the car fails an OBD emissions or smog test until the fault is repaired and the monitors are ready again.
Frequently asked questions
Why does my speedometer still work with P0715?
Speed readings come from the output shaft sensor or the ABS wheel sensors, not the input sensor. That's a useful clue: if only shift quality is affected, the input side is the one to look at.
Can I replace the input speed sensor myself?
On many cars it's held by one bolt on the outside of the case, so yes with basic tools. On models where it sits inside the transmission or in the control unit, the job needs fluid drained and often programming, which is shop work.
Is it the input or the turbine speed sensor?
Same job, different names. Some makers read the turbine shaft directly, others read a clutch drum turning at input speed; the code and diagnosis are the same.
Will a new sensor fix my harsh shifting?
If the only fault is the sensor circuit, usually yes after the codes are cleared and adaptation relearns. If slip or ratio codes were also stored, there may be internal wear that the sensor code was only revealing.