Error Code P0716 is defined as Input/Turbine Speed Sensor A Circuit Range/Performance. This is a generic but uncommon trouble code, meaning it applies to all vehicles equipped with the OBD-II system, especially those made since 1996 up to present. This code appears in vehicles with transmission fluid temperature sensor, such as Ford, Honda, Mazda, Mercedes Benz, Volkswagen, etc. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another.
Error Code P0716 is detected by the PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) when it detects a malfunction in the circuit for the designated input (or turbine) speed sensor A. Input and turbine speed sensors are identical virtually. Their only difference is the descriptive terminology. The A designation is reserved for OBD-II equipped vehicles that uses multiple input or turbine speed sensors. With this, it’s important to consult with the manufacturer’s service manual for the exact location of the input/turbine speed sensors designated A.
An input/turbine speed sensor is usually electromagnetic; it’s a 3-wire sensor that works by monitoring the transmission input speed (recognized by the PCM as revolutions per minute or RPMs). It’s positioned near the back of the torque converter (at the transmission input shaft) and can be either threaded directly into the transmission case or mounted through a bolt/stud.
On the transmission main (or input) shaft, there are grooves specially designed (or a notched reluctor wheel). To complete the electromagnetic circuit, the input shaft (or reluctor wheel) passes in close proximity to the end of the sensor. As the grooves (or notches) pass by the sensor, the circuit is interrupted; forming an electronic pattern is formed. The PCM then receives this pattern formation as a waveform pattern that it further interprets as transmission input/turbine speed.
The speed of transmission input/turbine speed is then compared with engine RPM speed, transmission output speed, engine load percentage, and vehicle speed to determine the right input speed RPM. If the actual input/turbine speed fails to coincide with the desired input/turbine speed, then the Check Engine lamp will be activated, and an error code will be stored.
In many instances, Error Code P0715 will place the vehicle into “limp mode,” which will cause the transmission to shift harshly. Some common symptoms include:
- Failure of the transmission to shift
- Erratic transmission shift points
- Increase in fuel consumption
- Speedometer fluctuation or malfunction
- The engine may stall when coming to a stop (for some cases)
Some of this code’s potential causes include:
- Defective output speed sensor
- Defective input speed sensor
- Bad transmission torque converter
- Broken, damaged, or worn reluctor ring or shaft
- Burned, loose, or damaged wiring and connectors
- Damaged or programming error in PCM
How to Check
To diagnose this code, you will need a diagnostic scanner, DVOM (digital volt/ohmmeter), a system wiring diagram, and a dependable vehicle information source. A portable oscilloscope can also help.
Start with a visual inspection of the wiring and connector system. Check for damages such as burnt, corroded, or disconnected wires and connectors. Repair or replace as necessary. Then, test the battery, including the cables and cable ends. Remove any sign of corrosion and secure the terminals (if applicable).
If both input and output sensor codes are present, then find the malfunctioning circuit using the scanner data stream. For a responsive data delivery, narrow the test to include only related data.
When removing the sensors, check for excessive metal debris on magnetic contact. Make sure to remove excessive debris before re-installing it again. When the sensors are removed, check the interruption grooves and reluctor wheel notches. Make sure to test individual sensors, use the DVOM, and follow the specifications set by the manufacturer (you can find this in the service manual). Replace faulty sensors that don’t comply with the specifications.
Disconnect any related controllers before testing the resistance and continuity using the DVOM. Not doing this could cause damage to the controller. Test the system circuits for open or shorted wiring. Repair or replace any defective circuits. If all system circuits and sensors are working properly, then you can suspect a defective or programming error in the PCM.
How to Fix
Depending on the diagnosis, common repairs for this code include:
- Replacement of the input speed sensor
- Replacement of failed output speed sensor
- Repair of damaged wiring for input speed sensor
- Repair or replacement of faulty wires, connectors, battery cables, battery cable ends, and cleaning of battery terminals
- The rebuilding of damaged transmission (from findings and contamination in transmission fluid)
- Repair of corroded connections
- Replacement of failed circuitry
Excessive metallic debris that is attached to the electromagnetic sensor can cause erratic input/output speed sensor readings.
Be careful when removing the sensors, as transmission fluid may escape from the opening. Some input speed sensor wiring can also be damaged by transmission fluid leaks, so make sure to check it as well when replacing wirings and/or sensors.
Sensor to reluctor clearance is crucial in some applications; make sure that mounting surfaces/threaded holes are free of any obstructions.
The most common mistake when dealing Error Code P0716 is quickly replacing the speed sensor when it’s not the cause of the problem. Wiring harness damage and contaminated transmission fluid are the common causes of this code. That’s why a thorough diagnosis is very important.