4R100

Output State Control (OSC) Mode

NOTE: In order to operate OSC, a KOEO On-Demand Self Test and a KOER On-Demand Self Test may need to be carried out to verify that no diagnostic trouble codes (DTCs) related to the digital transmission range (TR) sensor or the vehicle speed sensor (VSS) are present.

Output State Control (OSC) allows the technician to operate the main components of the transmission quickly and easily and provides accurate information to correctly diagnose the transmission. OSC allows the technician to take control of certain parameters to operate the transmission. For example, OSC allows the technician to shift the transmission only when commanding a gear change. If the technician commands first gear in OSC, the transmission will remain in first gear until the technician commands the next gear. For another example, the technician can command a shift solenoid to turn on or off while carrying out an electrical circuit check. OSC has two modes of operation for transmission, the BENCH MODE and the DRIVE MODE. Each mode/parameter has a unique set of vehicle operating requirements that the technician is required to meet before being allowed to operate OSC.

OSC-Transmission BENCH MODES
The BENCH MODE is functional only when the vehicle range selector is in PARK or NEUTRAL. The BENCH MODE may be used when the engine is either ON (running) or OFF (not running).
The BENCH MODE allows the technician to operate the following components:
- SSA - Commands the PCM to turn Shift Solenoid 1 OFF or ON.
- SSB - Commands the PCM to turn Shift Solenoid 2 OFF or ON.
- CCS - Commands the PCM to turn Coast Clutch Solenoid OFF or ON.
- TCC - Commands the PCM to turn Torque Converter Solenoid OFF or ON.
- EPC - Commands the PCM to control the Electronic Pressure Control Solenoid to OSC value.

SSA, SSB, CCS and TCC in BENCH MODE:
These OSC functions are used to turn SSA, SSB. CCS and TCC solenoids OFF and ON when carrying out an electrical check.
These OSC functions for parameters SSA, SSB, CCS and TCC allow the technician to choose the following options:
- OFF - turns solenoid OFF.
- ON - turns solenoid ON.
- XXX - cancels OSC value sent.

The vehicle requirements for sending an OSC value for SSA, SSB, CCS and TCC are as follows:
- Key ON and engine OFF (not running).
- Range selector lever in PARK or NEUTRAL.

The vehicle requirements must be met when sending the OSC value for SSA, SSB, CCS and TCC. If the vehicle requirements are not met when sending the OSC value, an error message will appear. When the error 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 Powertrain Control Module (PCM) (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.

EPC in BENCH MODE:
The BENCH MODE is used to test the functionality of the transmission's electronic pressure control. During BENCH MODE the EPC solenoid can ramp in increments of 15 psi from 0 to 90 psi and 90 to 0 psi. The technician should run the engine at approximately 1,500 rpm. The installation of a hydraulic pressure gauge is required to actually test whether the EPC solenoid and associated mechanical and hydraulic components are working correctly.
The OSC functions for the parameter EPC allow the technician to choose the following options:
- O0 - sets EPC pressure to 0 psi.
- 16 - sets EPC pressure to 15 psi.
- 30 - sets EPC pressure to 30 psi.
- 45 - sets EPC pressure to 45 psi.
- 60 - sets EPC pressure to 60 psi.
- 75 - sets EPC pressure to 75 psi.
- 90 - sets EPC pressure to 90 psi.
- XXX - cancels OSC for EPC.

The vehicle requirements for sending an OSC value for EPC in BENCH MODE are as follows:
- Key ON and engine ON (running at approximately 1,500 rpm).
- Range selector lever in PARK or NEUTRAL.

The vehicle requirements must be met when sending the OSC value for SSA, SSB, CC'S and TCC. If the vehicle requirements are not met when sending the OSC value, an error message will appear. When the error 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 Powertrain Control Module (PCM) (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.

OSC-Transmission DRIVE MODES:
The DRIVE MODE allows control of three transmission parameters. Each parameter has a unique set of vehicle operating requirements that the technician is required to meet before being allowed to operate OSC. The recommended procedure, when using the DRIVE MODE, is to control one parameter at a time.
The DRIVE MODE allows the technician to carry out the following functions on the transmission:
- GEAR - Commands the PCM to upshift or downshift.
- TCC - Commands the PCM to lock or unlock the torque converter clutch.
- EPC - Commands a high pressure value during an upshift or downshift.

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 exactly duplicate the vehicle condition for the customer complaint. For example, if the customer complains of 3-4 shift up a steep grade the technician can drive a vehicle up a steep grade and command a 3-4, 4-3 shift over and over again. Also, during the shift change the pressure is the exact pressure the vehicle normally produces. The transmission will stay in the gear that OSC has commanded until OSC commands another gear or OSC is canceled.
The OSC functions for the GEAR parameter allow the technician to choose the following options:
- 1 - PCM selects 1st gear.
- 2 - PCM selects 2nd gear.
- 3 - PCM selects 3rd gear.
- 4 - PCM selects 4th gear.
- XXX - Cancels OSC for GEAR and returns GEAR to normal mode.

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 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 Powertrain Control Module (PCM) (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.
Use the TCC parameter in OSC to first turn off the converter clutch before testing the transmission gear changes. This will allow evaluation of just the gear changes. If the torque converter clutch is not turned off, then the PCM may command the torque converter clutch to lock during a shift. This will make it difficult for the technician to tell whether a bad shift is the result of the torque converter clutch or the gear change itself.
The vehicle requirements for sending a GEAR value are as follows:
- Engine is running.
- Range selector lever is in OVERDRIVE.
- Vehicle speed is greater than 3km/h (2 mph).

TCC in DRIVE MODE:
This OSC function is used to test whether the torque converter clutch is engaging and disengaging correctly.
The OSC functions for the TCC parameter allow the technician to choose the following:
- ON - Commands TCC solenoid ON to lock the converter clutch.
- OFF - Commands TCC solenoid OFF to unlock the converter clutch.
- XXX - Cancels OSC for TCC and returns TCC to normal mode.

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 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 Powertrain Control Module (PCM) (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.
The vehicle requirements for sending the TCC value OFF are as follows:
- Engine is running.
- Range selector lever is in OVERDRIVE.
- Vehicle speed is greater than 3 km/h (2 mph).

The vehicle requirements for sending the TCC value ON are as follows:
- Engine is running.
- Range selector lever is in OVERDRIVE.
- Vehicle speed is greater than 3 km/h (2 mph).
- Transmission Fluid Temperature (TFT) is between 16°C - 135°C (60°F- 275°F).
- Brake is off when vehicle speed is below 32 km/h (20 mph).
- No excessive load on the engine.

EPC in DRIVE MODE:
This OSC function is used to increase pressures during an upshift or downshift to determine whether the pressure control system is functioning correctly. Harsher shifts indicate that the pressure control system works at higher pressures. The best way to isolate pressure control system problems, is to control the EPC in the bench mode and monitor a pressure gauge. The OSC functions far the parameter EPC allow the technician to choose the following options:
- 00 - sets EPC pressure to 0 psi.
- 16 - sets EPC pressure to 15 psi.
- 30 - sets EPC pressure to 30 psi.
- 45 - sets EPC pressure to 45 psi.
- 60 - sets EPC pressure to 60 psi.
- 75 - sets EPC pressure to 75 psi.
- 90 - sets EPC pressure to 90 psi.
- XXX - Cancels OSC for EPC. The vehicle requirements for sending the EPC value in drive mode are as follows:
- Engine is running.
- Range selector lever is in OVERDRIVE.
- Vehicle speed is greater than 3 km/h (2 mph).
- OSC value being sent is greater than what the normal strategy is commanding.

For example: If the PCM is commanding a pressure of 344.75 kPa (50 psi), an OSC value greater than 50 must be sent, sending a value of'60 or 7- would work. If the PCM is commanding 517.125 kPa (75 psi), sending a value of 60 would not work. but sending a value 90 would. This will make sure that OSC will only send a value greater than what the PCM is commanding, to prevent wear to the transmission due to inadequate pressures.
The vehicle requirements must be met when sending the OSC value for EPC. If the vehicle requirements are not met when sending the OSC value, an error message will appear. When the error 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 Powertrain Control Module (PCM) (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.

Using Output State Control (OSC) and Monitoring PIDs
To confirm that the OSC value was sent by the Scan Tool and the Powertrain Control Module (PCM) has accepted the OSC substitution, a corresponding PID for each OSC parameter must be monitored. After sending the OSC value the corresponding PID value should equal the OSC value. Additional PIDs should be monitored to help the technician adequately diagnose the transmission. The following is a list of PIDs to monitor while using OSC.

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To confirm that the OSC substitution occurred, SEND the OSC value and monitor the corresponding PID value. If no ERROR MESSAGE was received and the value of the corresponding PID is the same as the value sent from OSC, the OSC substitution was successful.