Programmable Speedometer/Odometer Module (PSOM)
DESCRIPTIONThe programmable speedometer/odometer module receives input from the rear brake anti-lock sensor, which is mounted on the rear axle differential housing. The PSOM processes this input signal information and relays it to the powertrain control module and the speed control module. This signal tells the powertrain control module the vehicle speed in miles per hour. Used as an input in determining shift scheduling and electronic pressure control.
SYMPTOMS
Harsh engagements, firm shift feel, abnormal shift schedule, unexpected downshifts may occur at closed throttle, abnormal torque converter clutch operation or engages only at Wide-Open Throttle (WOT). May flash transmission control indicator lamp.
DIAGNOSTIC TROUBLE CODES
452, P0500, P1500, P1501, P0503