Technical Description of OBD-II Trouble Code
No Signal in Input/Turbine Speed Sensor “B” Circuit
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to all vehicles manufactured from 1996 onwards (Ford, Honda, Mazda, Mercedes, VW, etc.). Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
When encountering a trouble code P2767, it indicates that the powertrain control module (PCM) has detected no voltage output from the circuit of the input (or turbine) speed sensor designated as “B”. Input and turbine speed sensors have similar designs and serve the same purpose, but manufacturers use different terminology to describe them.
The input/turbine speed sensor is typically a 3-wire, electromagnetic sensor used to monitor the transmission’s input speed, identified by the PCM as revolutions per minute (RPMs). The sensor is usually mounted with a bolt/stud or threaded directly into the transmission case, positioned near the rear of the bell housing (at the transmission input shaft).
Specially designed grooves or a notched reluctor wheel are permanently attached to the transmission’s main (or input) shaft. As RPMs are transferred from the engine to the transmission, the input shaft (or reluctor wheel) spins and passes close to the sensor. The steel shaft (or reluctor wheel) completes an electronic/electromagnetic circuit. The circuit is interrupted as the grooved (or notched) areas pass by the sensor, creating an electronic pattern. The PCM interprets this pattern formation as transmission input/turbine speed.
To determine the desired input RPM speed, the transmission input/turbine speed is compared with the engine RPM speed, percentage of engine load, and transmission output speed. If the actual input/turbine speed or system circuit voltage fails to coincide with the desired input/turbine speed or the manufacturer’s specified voltage, a code P2767 will be stored (and a malfunction lamp may be illuminated).
Symptoms
The P2767 code indicates a complete loss of circuit voltage for the input/turbine speed sensor. Symptoms of a P2767 code may include:
Causes
Possible causes for this code to be set are:
Diagnostic and Repair Procedures
A good starting point is always to check for technical service bulletins (TSB) specific to your vehicle. Your issue may be a known problem with a known solution provided by the manufacturer, which can save you time and money during diagnosis.
For diagnosing the P2767 code, a manufacturer’s service manual, an advanced diagnostic scanner, a digital volt/ohmmeter (DVOM), and possibly an oscilloscope will be helpful.
Experienced technicians usually begin the diagnosis with a visual inspection of the system’s wiring and connectors. Any shorted or open circuits and/or connectors must be repaired or replaced before proceeding. The battery, battery cables, and cable ends should be inspected. It is recommended to test the alternator output at this time.
Next, 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 as well.
If there are input sensor and output sensor codes present, use the scanner data stream to determine which circuit is malfunctioning. To retrieve the most accurate data from the scanner, narrow the data stream to include only relevant information.
Excessive metal debris on the magnetic contacts of the input and/or output speed sensors can cause sensor malfunctions. When removing the sensor, clean excessive debris from the magnetic surfaces before reinstalling. Also, inspect the interruption grooves and/or reluctor wheel notches for signs of damage or wear.
The DVOM can be used to test the resistance and circuit voltage of individual sensors. Follow the manufacturer’s specifications (found in the service manual or through All Data) and replace sensors that do not comply with the manufacturer’s specifications.
It is important to disconnect related controllers before testing resistance or continuity using the DVOM to avoid controller failure.
If a code P2767 is stored and 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:
