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Home >> Volvo >> 2007 >> S60 Base, AWD >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Transmission Control Module (TCM) Transmission Diagnostic Trouble Codes - 2 Of 7 >> TCM-0024: Transmission Speed Sensor, Input Speed. Faulty Signal (B5254T4, TF-80SC AWD; 2006-2007) >> Diagnostic trouble code (DTC) information

Diagnostic trouble code (DTC) information

Condition 

Fig 1: Identifying Transmission Output Speed Sensor
GLL149863Courtesy of VOLVO CARS OF NORTH AMERICA.

The signal for the input speed comes from a sensor inside the transmission control system. The transmission control module (TCM) bases its calculation of the speed of the input shaft after the torque converter on this signal. The signal is used to compare the speed of the gearbox with the vehicle speed. Using this comparison, the transmission control module (TCM) can calculate the gear shifting points.

The information on RPM and speed affects the adjustment of the system pressure (control of the lock-up function) and the reduction of the engine torque when changing gear. This results in smoother gear changes. The information is also used to control the lock-up function.

The transmission control module (TCM) calculates and compares also the gearbox input speed and output speed plus the engine speed for diagnosis. If the transmission control module (TCM) registers that the signal is incorrect when the vehicle speed is above approximately 7 km/h, the diagnostic trouble code (DTC) is generated.

The diagnostic trouble code (DTC) can be diagnosed at speeds above approximately 30 km/h and engine speeds above 400 RPM with at least 3rd gear engaged.

Substitute Value 

Possible Source 

Fault symptom[s]