P0727 Malfunction Code – Engine Speed Input Circuit No Signal

What is the P0727 fault description? What is the Engine Speed Input Circuit No Signal fault? How to fix P0727 fault code What are the causes and symptoms for the P0727 fault code

What is the P0727 Fault code? What does it all mean?

If the engine input shaft sensor speed sensor fails to send a signal to the powertrain controller module (PCM), a P0727 code is generated. The check engine light is also lit to notify the driver. On some vehicles, the malfunction lamp will light up immediately after a malfunction occurs. Other vehicles may require multiple malfunction cycles to illuminate.

Modern automatic transmission control systems require data inputs from multiple sources in order to effectively manage gear changes. Complex calculations are used to determine the gear shifting process.

The transmission control system must know four things to work properly. These are engine speed, engine load and currently selected gear. The throttle plate position tells the system whether the throttle is open or closed.

These four parameters are the minimum data that is required to allow any transmission control system operation. All shift points are determined by engine speed. However, the most important parameter of all four is the engine’s speed. RPM (revolutions per minute). Transmission control systems are programmed to shift gears at predetermined engine speeds in order to minimize component damage and exhaust emissions. This allows for maximum engine performance while using minimal fuel.

The transmission controller must have reliable and accurate data on the engine speed. If the PCM (or the transmission control unit (TCM), detects a fault in the input shaft speed sensor/associated electrical circuit or fails to receive signals from it, the system will be incapable of effectively controlling it and will emit a P0727 code.

P0727 fault codes can be found on many vehicle models, including those of Volkswagen, BMWs, Chevrolet, Hyundai and Volvo.

What causes the P0727 Fault code?

These are the most common reasons that P0727 is triggered

• – Defective motor input shaft speed sensor
• – There are metal deposits at the tip end of the input shaft speed sensor
• Defective transmission output speeds sensor
• – Defective input shaftspeed sensor reluctor wheel
• – Defective crankshaft position sensors (also used on some cars as speed sensors)
• – Damaged wires to sensor, loose connectors and open or short circuit problems
• – Defective shift solenoids
• – Defective hydraulic controller unit
• – Transmission fluid that is not working properly or is missing
• – A PCM is not working properly or has to be reprogrammed

What are the symptoms for P0727 Malfunction Codes?

You may experience the following symptoms if your vehicle has the code P0727:

• – Illumination at the check engine lights
• – Requires hard, delayed, and unpredictable shifting
• Transmission cannot change gears
• – Gearbox slip/slip
• – Increased fuel consumption
• – Non-working or wave speedometer
• Engine misfires
• – Engine hesitation during acceleration
• – Engine stalling during idling, or when it stops
• – PCM may enter failsafe mode (limp Mode) to limit engine power

How to Fix the P0727 Fault Code

First, the PCM fault codes must be read using a scanner. Usually, P0727 is set with other codes. After checking the code, the mechanic should test the vehicle to determine if it can be cleared. Next, inspect the wiring and connectors to the engine speed input sensor as well as the sensor circuit. Any corrosion should be cleaned and replaced with newer cables. It is important to repair loose connectors and test the vehicle again. If the code is returned, your mechanic should test the input speed sensor reference potential. In both circuits, continuity and resistance must be verified. The sensor should fail these tests and be replaced.

Near the front of the input shaft is the engine speed sensor, which can be found inside the transmission box. The rubber O-ring seals the sensor housing with the transmission case. To collect any fluids that may have escaped from the sensor housing, you should place it under the transmission. Hot transmission fluid can cause serious health problems if the sensor is removed from its housing.

There are several repairs that can resolve the P0727 fault code.

• – Replacing the defective motor input shaft sensor speed sensor
• – Replace the defective transmission output speed sensor
• – Replace the crankshaft position sensor
• – Repair damaged wires, connectors and open or short circuits to sensors
• – Replacing the defective motor input speed sensor reluctor wheel
• – Replacing a defective shift solenoid
• – Refilling the transmission fluid that is not available
• – Replacing dirty or contaminated transmission oil
• – Replacing/reprogramming the PCM

How Serious Is the P0727 Fault Coding?

Your vehicle should be inspected immediately if it has a P0727 code. Accidents can occur when the engine suddenly stops during deceleration in heavy traffic. This can lead to many problems in driving, including fuel consumption increases and engine stumbling while accelerating. If the gear isn’t shifted correctly, or is stuck, it could cause damage to the transmission.