Diagnostic trouble code (DTC) information

Condition 

Fig 1: Identifying Automatic Transmission Gear Shifter With Manual Gear Change

Courtesy of VOLVO CARS OF NORTH AMERICA.

The transmission control module (TCM) and the gear selector module (GSM) communicate with each other over a network via a standardized serial communication protocol, Local Interconnect Network (LIN), to exchange information. The control modules both send and receive information.

If the transmission control module (TCM) registers the signal from the gear selector module (GSM) is too high or too low, the diagnostic trouble code (DTC) is generated.

The diagnostic trouble code can be diagnosed when the ignition is on.

Substitute Value 

• Manual gearchange "Man  " function block.
• The function Sport program S  is blocked.

Possible Source 

• The communication lead between the gear selector module (GSM) and the transmission control module (TCM) short-circuited to voltage or ground.

Fault symptom[s] 

• General warning lamp lit
• Gear selector indicator not working.