The powertrain control module (PCM) is a component in your vehicle. This component controls the entire engine and transmission. To do its job, the PCM relies on a number of sensors. P0725 indicates that one of the sensors is malfunctioning. Three different names are given to the problematic sensor:
- Engine speed sensor
- Transmission speed sensor
- Speed sensor
The same sensor is referred to by all of these sources, regardless of the name. The PCM is notified by the speed sensor when it’s time to change gears. The P0725 code is set if there is no signal received by the PCM from the speed sensors, if it does not increase slowly, if it is irregular or variable, or even if there is not a signal at all.
Table of Contents
What are the P0725 Fault Symptoms?
The PCM will not be able to measure the vehicle’s speed if the speed sensor is broken. This can lead to many other systems malfunctioning. Some symptoms include:
- The engine fault lamp illuminates
- The gearbox is not able to change gears
- Delay or irregular gear changes
- Faulty odometer
- Faulty Tachometer
- The PCM can put the vehicle in protective mode (Limp Mode)
- Misfiring engine and stalling
What causes the P0725 Fault?
- Faulty engine input speed sensorFaulty output speed speed sensor
- Broken, loose or worn connectors
- Cables damaged or shorted out
- Valve body or other pressure-related issues
- Transmission oil dirty or low?
- Faulty gearshift solenoids
- PCMs can be faulty, but this is rare.
P0725 Fault Code: How serious is it?
All the symptoms above can pose a threat to your driving safety. They can also damage the gearbox which is one the most expensive components of a vehicle to repair or replace. It is easy to check and replace the sensor. This fault code should be taken seriously. Repair it before further damage is done to your car.
How to Fix the P0725 Fault?
You must first determine the cause of the fault. The fault code will most likely be caused by a defective sensor or circuitry. It is logical that the sensor would emit this error code if it were damaged. Metal deposits may also have accumulated on the sensor. The problem could be electrical, rather than mechanical. The PCM won’t receive a signal if the connectors or circuit are damaged. This is true even if the sensors work. There is no electrical issue if the PCM receives a signal even though the sensor is faulty. You should then check the gearbox if there is no fault with the circuits or sensor.
- Replace the engine speed sensor
- Replace the output speed sensor
- Replace damaged connectors and cables
- Replace the solenoids
- Replace transmission fluid and filter
- Repair transmission fluid leaks
Frequently Asked Questions about P0725
Why does the transmission need to know engine speed?
The transmission must know the speed of rotation so that it can:
Know when to shift?
Control shift smoothness
Protect transmission from damage
No engine speed = poor shifting decisions
Why does P0725 have such a big impact on shifting?
Transmissions shift blindfolded without engine speed information.
It may be:
Late shift
Shift hard
Skip gears
Lock into a safe mode
Transmissions don’t like guessing.
Why does P0725 appear with no tachometer motion?
Many cars use the same speed signal to:
Transmission
Tachometer
Cruise control
The tachometer can fall to zero if the signal is lost or behave strangely.
Can the crankshaft sensors cause P0725?
Yes, it happens quite often.
Crankshaft position sensors are usually the primary source of engine speed information.
Why does P0725 come and go sometimes?
Because heat matters.
The sensor can:
Work when its cold but fail when hot
Recover after cooling down
This makes the problem seem “random.”
What happens if you ignore P0725?
Transmission in limp mode
Harsh shifting damages clutches
Fuel efficiency drops
Driving becomes unpredictable
