P0715

A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.

Safe to drive

Usually drivable a short distance if it still shifts. If it locks into limp mode, avoid highway speeds — the drop into a single fixed gear can arrive without warning and takes away your ability to accelerate out of a hazard. Get it inspected promptly.

Urgency

Get it looked at now

Will it pass emissions

Not affected

If ignored

Repeated harsh or slipping shifts under default strategy wear clutch friction material and cook the fluid. A cheap sensor or connector fault left alone for months can turn into an internal transmission repair costing many times more.

Check engine light

Solid

• Check engine or transmission warning light on
• Harsh, delayed, or missing shifts
• Possible limp mode (locked in one gear)
• Slipping or shuddering during gear changes

Many vehicles show no symptom at all beyond the warning light. The absence of a symptom does not mean the fault is not real.

These are the causes this code can have. For the order to work through them in, see what to check first.

Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.

In order. Each of these is cheaper or faster than what follows it, and each one can make the rest unnecessary.

1. Transmission fluid level, color and smell

   Costs nothing and rules out the condition that makes every transmission symptom worse. Burnt fluid or metal glitter also tells you whether you are chasing a sensor or an internal failure.

2. Freeze frame and whether the code is pending, current or history

   Tells you whether the fault is constant or intermittent, and at what speed, load and fluid temperature it appears. An intermittent that only shows up hot points at wiring or a heat-sensitive sensor.

3. The transmission case connector for fluid, corrosion and backed-out pins

   Transmission fluid wicks up the harness and into the connector, and once it is in there the terminals corrode and the signal drops out. It costs nothing but a few minutes with the connector unplugged, so rule it out before ordering a sensor.

4. Live data: engine RPM, input/turbine speed and output speed together

   With the torque converter clutch locked, input speed should track engine RPM closely. A flat zero, a spiky trace or a value that will not follow RPM tells you immediately whether the signal is dead, noisy or just biased.

5. Other stored codes across all modules

   A companion ratio or slip code changes the picture from electrical to mechanical. A network or lost-communication code matters for a different reason: the input speed sensor itself is hardwired to the module, but the plausibility check that sets this code compares it against engine RPM and vehicle speed arriving over the bus, so losing those can set the code with a perfectly healthy sensor and wire.

1. Record the full picture before clearing anything

   Tools Bidirectional scan tool with transmission data access

   Scan every module, not just the engine controller. Save freeze frame, note the code status, and write down fluid temperature, vehicle speed and gear at the moment of the fault. Clear the code only after you have the data.

   Expected

   Freeze frame captured; you know whether the fault is constant or condition-dependent

2. Compare the three speed signals in live data

   Tools Scan tool with graphing, safe road-test route

   Watch engine RPM, input/turbine speed and output shaft speed on one graph. Do it at idle in Park, at idle in Drive with the brake held, and on a road test through every gear.

   Expected

   Input speed should rise and fall smoothly with road speed, and should sit very close to engine RPM whenever the converter clutch is applied

3. Inspect and wiggle-test the harness and case connector

   Tools Bright light, pick set, terminal drag tester

   Unplug the connector at the transmission. Look for transmission fluid inside it, green or white corrosion, spread or backed-out terminals, and melted insulation where the harness passes near the exhaust. Reconnect and wiggle the harness while watching live data or a scope.

   Expected

   Clean dry terminals with firm pin tension; no signal dropout during the wiggle test

4. Test the sensor at its own connector

   Tools DMM, oscilloscope, factory service information

   Identify the sensor type first — it varies by vehicle. A two-wire variable reluctance sensor is passive: check winding resistance and look for an AC voltage output as the shaft turns. A three-wire Hall-effect sensor is powered: verify reference voltage and ground are present, then scope the signal for a clean square wave. Resistance and voltage specifications are vehicle-specific; use the factory service data for the number.

   Expected

   A clean repeating waveform whose frequency rises with shaft speed, with no dropouts, and supply and ground within spec for a powered sensor

5. Test the wiring between sensor and module

   Tools DMM, wiring diagram for the specific vehicle

   With the harness disconnected at both ends, check each circuit for continuity end to end, for a short to ground, for a short to power, and for a short between the two sensor circuits. On a shielded circuit, confirm the shield drain is intact and grounded at one end only.

   Expected

   Near-zero resistance end to end on each circuit and open to ground, power and each other

6. Remove the sensor and inspect the tip and reluctor

   Tools Sockets, inspection light, borescope where access is poor

   Pull the sensor and examine the tip. A light dusting of fine metal is normal on a magnetic sensor. A heavy furry coat of ferrous debris means internal wear and changes the whole diagnosis. Check the tone ring or reluctor for missing or damaged teeth where you can see it, and check that the sensor seats fully with the correct O-ring.

   Expected

   Clean tip, intact teeth, sensor seating fully with an undamaged seal

7. Confirm the signal actually reaches the module

   Tools Oscilloscope, back-probe leads, connector pinout for the specific vehicle

   Back-probe the module connector with the system running and scope the signal there. If the waveform is correct at the module pin but the scan tool still shows zero input speed, the fault is inside the module or in its software.

   Expected

   The same clean waveform at the module pin as at the sensor

8. Check for manufacturer bulletins before condemning hardware

   Tools Manufacturer service bulletin database

   Several manufacturers have issued software updates or revised sensor and harness parts for this code on specific transmissions. Search bulletins by exact year, engine and transmission code before ordering parts.

   Expected

   Either a bulletin that matches your symptom exactly, or a clear absence of one

US independent shop estimates, parts plus labor, in whole dollars. Labor dominates and varies enormously with where the sensor sits — some are a ten-minute job from under the hood, others need the pan or the valve body out. Confirm the location for your specific transmission before assuming the low end applies. On the overhaul line, the low end reflects a common rear-drive 4- or 6-speed with a remanufactured unit available; 8- and 10-speed automatics, CVTs and transverse units with heavy removal labor routinely land above $6,500.

• Replacing the sensor first because it is the named part. Connector corrosion and fluid-soaked harnesses are just as common and cost far less to fix.
• Ignoring metal debris on the sensor tip. A sensor loaded with ferrous material is reporting an internal wear problem, and a new sensor will fail again.
• Clearing the code before capturing freeze frame, then losing the only evidence about when the fault occurs.
• Testing a Hall-effect sensor as if it were a passive magnetic pickup. Measuring resistance across a powered three-wire sensor tells you nothing useful.
• Condemning the module because the scan tool shows zero, without scoping the actual signal arriving at the module pin.
• Assuming limp mode itself is the failure. Limp mode is the module protecting the transmission after losing the signal — fix the signal and limp mode goes away.

• Transmission Input Speed Sensor
• Transmission Input Speed Sensor Wiring

• P0714Transmission Fluid Temperature Sensor A Circuit IntermittentSeverity level 3 of 5: Diagnose soon.moderate
• P0716Input/Turbine Speed Sensor "A" Circuit Range/PerformanceSeverity level 4 of 5: Get it looked at now.high

Definition

Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.

Diagnostic guidance

Written and reviewed in-house. See our editorial policy.

Review status

Reviewed

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