Technical Description of OBD-II Trouble Code
The circuit range/performance of the Input/Turbine Speed Sensor A is causing this diagnostic trouble code (DTC). This code is a generic powertrain code that applies to all vehicles made in 1996 or later (such as Ford, Honda, Mazda, Mercedes, VW, etc.). The specific repair steps may vary depending on the make and model of the vehicle.
What does that mean?
When the powertrain control module (PCM) detects a malfunction in the circuit for the designated input (or turbine) speed sensor known as A, it triggers the diagnostic trouble code P0716. Although input and turbine speed sensors have similar designs, some manufacturers use different component terminology. The A designation is typically used for OBD-II equipped vehicles that have multiple input or turbine speed sensors.
The input/turbine speed sensor is an electromagnetic, 3-wire sensor that monitors the transmission input speed (measured in revolutions per minute or RPMs) as recognized by the PCM. It is located near the rear of the torque converter, either mounted with a bolt/stud or threaded directly into the transmission case.
On the transmission main (or input) shaft, there are specially designed grooves (or a notched reluctor wheel). These grooves or notches pass by the sensor, interrupting the electromagnetic circuit and forming an electronic pattern. The PCM receives this pattern as a waveform pattern, which it interprets as the transmission input/turbine speed.
The PCM compares the transmission input/turbine speed with the engine RPM speed, percentage of engine load, and transmission output speed to determine the desired input speed RPM. If the actual input/turbine speed does not match the desired speed, a code is stored and a malfunction lamp may illuminate.
Symptoms & Severity
In some cases, when this code is stored, the PCM will put the transmission in ‘limp-in’ mode, causing harsh shifting. If you experience irregular shifting when presented with a P0716 code, it is important to address the problem immediately.
Symptoms of a P0716 code may include:
Causes
Possible causes for this code to be set are:
Diagnostic and Repair Procedures
A good starting point is to check for technical service bulletins (TSB) specific to your vehicle. There may be a known issue with a known fix provided by the manufacturer, which can save time and money during diagnosis.
To diagnose the P0716 code, you will need an advanced diagnostic scanner, a digital volt/ohmmeter (DVOM), a manufacturer’s service manual, and possibly an oscilloscope.
Begin the diagnosis with a visual inspection of the system wiring and connectors. Repair or replace any disconnected, corroded, burnt, or shorted wiring and/or connectors. Also, test the battery and inspect the battery cables and cable ends. Test the alternator output as well.
Connect the scanner to the diagnostic port and retrieve all stored codes. Write them down for future reference and make a note of the freeze frame data.
If input sensor and output sensor codes are present, use the scanner data stream to determine which circuit is at fault. Narrow the data stream to include only pertinent information for more accurate data.
Check for excessive metal debris on the magnetic surfaces of the input and/or output speed sensors. Remove excessive debris before reinstalling. Also, inspect the interruption grooves and/or reluctor wheel notches.
Use the DVOM to test individual sensors according to the manufacturer’s specifications. Replace sensors that do not comply with the specifications. Some manufacturers recommend replacing both the input and output speed sensors as a set. Before testing resistance and continuity with the DVOM, disconnect related controllers to avoid controller failure.
If all system circuits and sensors are in proper working order and comply with the manufacturer’s specifications, suspect a faulty PCM or a PCM programming error.
Additional diagnostic notes:
