P0718 Code Meaning and Next Steps

First checks take 10 minutes for basic checks. No special tools are usually needed for the first checks.

Can you keep driving?

Stop driving if any of these apply

!The vehicle suddenly runs much worse, loses power sharply, or the check-engine light starts flashing.
!There is a strong smell, smoke, overheating, or any symptom that suggests a real-time safety problem rather than a stored code alone.

If the light is steady and the vehicle still drives normally: Often yes for a short time, but it should not be ignored if drivability changes are obvious.

What to check first

Step-by-step checks

1
Safety first
Avoid driving hard if the transmission is slipping, harshly shifting, or in limp mode
2
Free - no tools
Inspect the sensor connector and harness for contamination or damage
3
Basic tool needed
Check whether the transmission is actually slipping or if only the signal is wrong
4
Basic tool needed
If scan data is available, compare input speed with engine RPM and shift behavior
5
Basic tool needed
Look for related speed-sensor or ratio codes that can help narrow the fault
6
Basic tool needed
Notice whether the code appeared after transmission service or fluid work

If the code returns

-If the signal is implausibly high, wiring or sensor failure becomes more likely.
-If the sensor signal looks good but the transmission still acts wrong, inspect the internal transmission side.
-If the code returns after connector service, recheck sensor fit and wiring routing.

Background

What this code means

P0718 is a generic OBD-II code for a high-input input/turbine speed sensor signal.

That usually means the ECU is seeing a signal that is too high for the operating condition, or the sensor circuit is behaving badly. Sensor damage, wiring faults, or internal transmission issues can all be involved.

Diagnosis

Common causes

Most common

Failed input shaft speed sensor

The sensor may no longer report a believable input speed value.

Common

Connector or wiring damage

Heat, fluid contamination, or corrosion can distort the signal.

Common

Debris on the sensor tip

Metal debris can skew the sensor reading.

Possible

Internal transmission fault

A mechanical or hydraulic problem can make the signal appear too high.

Avoid these mistakes

What not to do

xDo not replace the module first if the sensor circuit is clearly damaged.
xDo not keep driving hard if the transmission is slipping or in limp mode.

Parts

Parts that may need replacing

PartTypical costNotes

Input shaft speed sensor$40-$180Most relevant when the sensor signal is too high or implausible.

Connector or wiring repair$50-$250Often the actual fix when the circuit is contaminated or intermittent.

Internal transmission repair$800-$3,000Relevant when the sensor is fine but the gearbox is not behaving correctly.

Related OBD codes

P0716

P0716 means the input shaft speed sensor is reading outside the expected range.

P0717

P0717 means the input shaft speed sensor signal is reading too low or not present.

P0721

P0721 means the output shaft speed sensor range or performance is not believable.

Source notes

Generic OBD-II (SAE J1979 / ISO 15031-5). P0718 was seeded from dtcdb and then expanded around high-input input shaft speed sensor faults, with emphasis on sensor, wiring, and internal transmission checks.

This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.

This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.

Last reviewed: 2026-04-10

Reference: Open reference

P0718 - The Input Shaft Speed Sensor Signal Is Reading Too High