Scan Tool Testing and Procedures

Output State Control (OSC) Mode

NOTE: Retrieve continuous codes and carry out a KOEO and KOER On-Demand Self Test before using output state control (OSC). Any 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 PCM will not allow the OSC to operate.

OSC on the scan 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 scan tool 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:
^ SSA/SS1 - Directs PCM to command Shift Solenoid A OFF or ON
^ SSB/SS2 - Directs PCM to command Shift Solenoid B OFF or ON
^ SSC/SS3 - Directs PCM to command the current to the 3-2 Timing/Coast Clutch Solenoid
^ TCC - Directs PCM to command the Torque Converter Solenoid from 0% duty cycle to 100% duty cycle
^ LINEDSD - Directs PCM to command line pressure from 0 to 300 PSI. The PCM will command the appropriate PCA current to obtain the commanded line pressure.
^ PCB - Directs PCM to command pressure control solenoid B from 0 to 500 PSI. The PCM will command the appropriate PCB solenoid current to obtain the commanded pressure.

SSA/SS1, SSB/SS2, SSC/SS3 and TCC in Bench Mode
These OSC functions are used to command SSA/SS1, SSB/SS2, SSC/SS3 and TCC solenoids OFF and ON when carrying out an electrical circuit check.

The OSC functions for parameters SSA/SS1, SSB/SS2 and SSC/SS3 allows the technician to choose the following options:
^ OFF - Directs PCM to command the solenoid OFF.
^ ON - Directs PCM to command the solenoid ON.

The OSC options to control TCC for the torque converter clutch solenoid in Bench Mode are as follows:
^ 0% - Commands PCM to control duty cycle to 0%.
^ 100% - Commands PCM to control duty cycle to 100%.

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 SSA/SS1, SSB/SS2, SSC/SS3 and 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 SSA/SS1, SSB/SS2, SSC/SS3 and TCC commands. If the vehicle requirements are not met when sending the OSC value, the command is canceled. After sending the OSC value, if the vehicle requirements are no longer met, the OSC value will be canceled by the PCM (monitoring corresponding PID).

LINEDSD and PCB in Bench Mode
The LINEDSD in Bench Mode may be used when carrying out an electrical check on the line pressure control (LPC) or PCB solenoids or used to test the functionality of the transmission's electronic control of the line pressure. When testing the LPC or PCB for controlling the line pressure the technician is required to run the engine greater then 1,500 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 LPC/PCB solenoid and other associated mechanical and hydraulic components are working correctly.

The OSC functions for the parameter LINEDSD and PCB allows the technician to choose pressure between 0 and 300 psi for LINEDSD and between 0 and 500 psi for PCB:

The vehicle requirements for sending an OSC value for LINEDSD and PCB in Bench Mode is as follows:
^ Key on/Engine running, engine speed greater then 1,500 rpm.
^ Gear selector in PARK or NEUTRAL.

The vehicle requirements must be met when sending the OSC value for LINEDSD or PCB. If the vehicle requirements are not met when sending the OSC value, the command will be canceled. After the OSC value for LINEDSD or PCB is sent, if the vehicle requirements are no longer met, the command will be canceled.

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:
^ GEAR - Directs the PCM to upshift or down shift.
^ OSC-TCC - Directs the PCM to engage or disengage the torque converter clutch.

GEAR 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 GEAR 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.

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, the command will be canceled. After the OSC value for GEAR is sent, if the vehicle requirements are no longer met, the command will be canceled.

It is recommended to use the OSC-TCC 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 GEAR 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

OSC-TCC 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:
^ NORMAL - Allows the PCM to control the TCC normally.
^ LOCK - Commands TCC solenoid ON (100% duty cycle) to engage the converter clutch.
^ UNLOCK - Commands TCC solenoid OFF (0% duty cycle) to disengage the converter clutch.

The vehicle requirements must be met when sending the OSC value for OSC-TCC. If the vehicle requirements are not met when sending the OSC value, the command will be canceled. When the command is canceled, OSC is aborted and must be restarted. After the OSC value for OSC TCC is sent, if the vehicle requirements are no longer met, the OSC value will be canceled by the PCM (monitoring corresponding PID).

The vehicle requirements for SENDING the OSCTCC value LOCK 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

The vehicle requirements for SENDING the OSC-TCC value UNLOCK is as follows:
^ Engine is running
^ The selector lever is in (D)
^ Vehicle speed is greater than 3 km/h (2 mph)

Using Output State Control (OSC) and Monitoring PIDs
To confirm that the OSC value was sent by the scan tool 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. The following is a list of PIDs to monitor while using OSC.