Scan Tool Testing and Procedures
Output State Control (OSC) ModeNOTE: Retrieve continuous codes and carry out a KOEO & KOER On-Demand Self Test before using output state control (OSC). Any diagnostic trouble codes (DTCs) related to the transmission range (TR) sensor, output shaft speed (OSS) sensor or the vehicle speed sensor (VSS) must be fixed first or the powertrain control module (PCM) will not allow the OSC to operate.
OSC on the NGS or WDS diagnostic tool allows the technician to easily and quickly control the main functions and components of this transmission. OSC is used to help test the electrical, hydraulic or mechanical concerns related to the transmission. The NGS or WDS also provides PID information, along with the OSC functions, to accurately diagnose the transmission. For example, OSC allows the technician to shift the transmission, engage the converter clutch, or command line pressure or turn a solenoid off and on. OSC has 2 menus for operation, the BENCH MODE and the DRIVE MODE.
OSC - BENCH MODE
The BENCH MODE is functional only when the gear selector is in PARK or NEUTRAL. The BENCH MODE may be used when the engine is either ON (running) or OFF. The BENCH MODE allows the technician to function the following components:
^ SS1 - Directs PCM to command Shift Solenoid A OFF or ON
^ SS2 - Directs PCM to command Shift Solenoid B OFF or ON
^ SSB_AMP - Directs PCM to command the current to the 3-2 Timing/Coast Clutch Solenoid
^ TCC - Directs PCM to command the Torque Converter Solenoid OFF or ON (OFF = 0% duty cycle and ON = 100% duty cycle)
^ LINEDSD - Directs PCM to command line pressure to either 50, 75, 100, 125, 150, 175, 200 PSI. The PCM will command the appropriate PCA current to obtain the commanded line pressure.
SS1, SS2, SSB_AMP and TCC in BENCH MODE
These OSC functions are used to command SS1, SS2, SSB_AMP and TCC solenoids OFF and ON when carrying out an electrical circuit check.
The OSC functions for parameters SS1, SS2 and TCC allows the technician to choose the following options:
^ OFF - Directs PCM to command the solenoid OFF
^ ON - Directs PCM to command the solenoid ON
^ XXX - Cancels OSC command (returns solenoid to normal operation)
The OSC options to control SSB_AMP for the 3-2 Timing/Coast Clutch Solenoid in Bench Mode are as follows:
^ 0 - Commands TCM to control current to zero amps
^ 0.25 - Commands TCM to control current to 1/4 amp or 250 milliampere
^ 0.50 - Commands TCM to control current to 1/2 amp or 500 milliampere
^ 0.75 - Commands TCM to control current to 3/4 amp or 750 milliampere
^ 1 - Commands TCM to control current to 1 amp or 1000 milliampere
^ XXX - Cancels OSC and allows the PCM/TCM normal control of the VFS solenoids
Controlling the solenoids allows the technician to measure the circuit current using an inductive pickup or to measure the circuit voltage when carrying out electrical tests.
The vehicle requirements for SENDING an OSC value for SS1, SS2, SSB_AMP or TCC are as follows
^ Key on/engine off or key on/engine running at idle
^ Gear selector in PARK or NEUTRAL
The vehicle requirements must be met when sending the OSC value for SS1, SS2, SSB_AMP and TCC solenoids. If the vehicle requirements are not met when sending the OSC value, an ERROR MESSAGE will appear. When the ERROR MESSAGE is received, OSC is aborted and must be restarted. After sending the OSC value, if the vehicle requirements are no longer met the ERROR MESSAGE will not appear but the OSC value will be canceled by the PCM (monitoring corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.
LINEDSD in BENCH MODE
The LINEDSD in BENCH MODE may be used when carrying out an electrical check on the EPC solenoid or used to test the functionality of the transmission's electronic control of the line pressure. When testing the EPC for controlling the line pressure the technician is required to run the engine greater then 1500 RPM. The hookup of a hydraulic pressure gauge is required to actually test whether the transmission line pressure is correct. This will test whether the hydraulic pump, the pressure regulator and the EPC solenoid and other associated mechanical and hydraulic components are working properly.
The line pressure may be commanded between 60 PSI and 180 PSI. When carrying out an electrical test on the EPC solenoid, set LINEDSD to 180 PSI to command the EPC solenoid OFF and 75 PSI to command the PCA solenoid ON. Commanding the 180 PSI may not electrically turn the pressure solenoid completely off and commanding 75 PSI may not electrically turn the pressure solenoid completely on.
The OSC functions for the parameter LINEDSD allows the technician to choose the following options:
^ 75 - Directs PCM to command line pressure to 75 PSI
^ 100 - Directs PCM to command line pressure to 100 PSI
^ 125 - Directs PCM to command line pressure to 125 PSI
^ 150 - Directs PCM to command line pressure to 150 PSI
^ 175 - Directs PCM to command line pressure to 175 PSI
^ XXX - Cancels OSC command line pressure (returns to normal operation)
The vehicle requirements for sending an OSC value for LINEDSD in BENCH MODE is as follows:
^ Key on/engine off or key on/engine running (engine speed greater then 1500 RPM)
^ Gear selector in PARK or NEUTRAL
The vehicle requirements must be met when sending the OSC value for PCA. If the vehicle requirements are not met when sending the OSC value, an ERROR MESSAGE will appear. When the ERROR MESSAGE is received, OSC is aborted and must be restarted. After the OSC value for PCA is sent if the vehicle requirements are no longer met the ERROR MESSAGE will not appear but the OSC value will be canceled by the PCM (monitoring corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.
OSC - DRIVE MODE:
The DRIVE MODE allows control of 2 transmission functions. Each OSC function has a unique set of vehicle operating requirements that the technician is required to meet before he/she is allowed to operate OSC. The recommended procedure, when using the DRIVE MODE, is to command one parameter at a time. The DRIVE MODE allows the technician to control the following OSC functions on the transmission:
^ OSCGEAR - Directs the PCM to upshift or down Shift
^ OSCTCC - Directs the PCM to engage or disengage the torque converter clutch
OSCGEAR in DRIVE MODE:
This OSC function is used to test the transmission gear changes. The advantage of using OSC for changing gears is to allow the technician to easily test a specific gear and/or upshift or down shift that has been identified as the customer complaint. When using the OSC to command a shift change, the PCM should command the correct or normal pressure for that shift. The transmission will remain in the gear that OSC has commanded until OSC commands another gear or OSC is cancelled.
The OSC functions for the OSCGEAR parameter allow the technician to choose the following options:
^ 1 - Directs PCM to command 1st gear
^ 2 - Directs PCM to command 2nd gear
^ 3 - Directs PCM to command 3rd gear
^ 4 - Directs PCM to command 4th gear
^ XXX - Cancels OSC command for GEAR (returns to normal operation)
The vehicle requirements must be met when sending the OSC value for GEAR. If the vehicle requirements are not met when sending the OSC value, an ERROR MESSAGE will appear. When the ERROR MESSAGE is received, OSC is aborted and must be restarted. After the OSC value for GEAR is sent if the vehicle requirements are no longer met the ERROR MESSAGE will not appear but the OSC value will be canceled by the PCM (monitoring corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.
It is recommended to use the OSCTCC parameter in OSC to first turn off the converter clutch when testing the transmission gear changes. This will allow the technician to evaluate just the gear changes. If the torque converter clutch is not turned off, then the PCM may command the torque converter clutch to engage during a shift. This could make it more difficult for the technician to determine whether a bad shift is the result of the torque converter engaging or the actual gear change.
The vehicle requirements for SENDING a OSCGEAR value is as follows:
^ Engine is running
^ Gear selector is in (D)
^ Vehicle speed is greater than 3 km/h (2 mph)
^ Vehicle speed must be lower than 48 km/h (30 mph) to command a downshift to 1st gear
^ Vehicle speed must be lower than 96 km/h (60 mph) to command a downshift to 2nd gear
^ Vehicle speed must be lower than 145 km/h (90 mph) to command a downshift to 3rd gear
^ Vehicle speed must be greater than 48 km/h (30 mph) to command an upshift to 4th gear
OSCTCC in DRIVE MODE
This function is used to test whether the torque converter clutch is locking and unlocking correctly.
The OSC functions for the TCC parameter allows the technician to choose the following:
^ ON - Commands TCC solenoid ON (100% duty cycle) to engage the converter clutch.
^ OFF - Commands TCC solenoid OFF (0% duty cycle) to disengage the converter clutch.
^ XXX - Cancels OSC for TCC (returns to normal operation)
The vehicle requirements must be met when sending the OSC value for TCC. If the vehicle requirements are not met when sending the OSC value, an ERROR MESSAGE will appear. When the ERROR MESSAGE is received, OSC is aborted and must be restarted. After the OSC value for TCC is sent if the vehicle requirements are no longer met the ERROR MESSAGE will not appear but the OSC value will be canceled by the PCM (monitoring corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.
The vehicle requirements for SENDING the OSCTCC value OFF is as follows:
^ Engine is running
^ Gear selector is in Overdrive
^ Vehicle speed is greater than 3 km/h (2 mph)
The vehicle requirements for SENDING the OSCTCC value ON is as follows:
^ Engine is running
^ Gear selector is in (D)
^ Vehicle speed is greater than 3 km/h (2 mph)
^ Transmission fluid temperature (TFT) is between 16°C (60°F) and 116°C (240°F)
^ Brake is off when vehicle speed is below 32 km/h (20 mph)
^ Not an excessive load on the engine
^ Not during an upshift or downshift
^ Engine speed is greater then 1,500 rpm
Using Output State Control (OSC) and Monitoring PIDs
To confirm that the OSC value was sent by the NGS and the PCM has accepted the OSC command, a corresponding PID for each OSC parameter must be monitored. After sending the OSC value, the corresponding PID value should be the same as the OSC value. Additional PIDS should be monitored to help the technician accurately diagnose the transmission.