Output State Control (OSC) Mode
Output State Control (OSC) ModeDescription
Output state control (OSC) allows an off-board diagnostic scan tool direct control of specific transaxle components or functions. OSC allows the technician to control the main functions or components of the transaxle to help the technician more quickly and easily diagnose the transaxle. For example, OSC may be used to change gears or remain in a specific gear. OSC may be used to control the operation of the torque converter clutch (TCC) to engage or disengage, or to keep the converter clutch from engaging at all. OSC may also be used to help carry out solenoid electrical pinpoint tests by turning a solenoid off or on by controlling the actual current to the VFS solenoid.
Procedure
NOTE: Retrieve Continuous Codes and carry out a KOEO and KOER On-Demand Self Test before using any OSC. Any DTCs related to the transmission range (TR) sensor, the output shaft speed (OSS) sensor or the turbine shaft speed (TSS) sensor must be fixed or the PCM will not allow the OSC to operate.
OSC is used to test various transaxle components and functions when the vehicle is either in the service bay or being driven on the road. Specific vehicle conditions are required for OSC to control each specific function or component. The following will describe which transaxle functions and components OSC may control and the specific vehicle conditions necessary for its operation.
Service Bay - Vehicle State No. 1
Vehicle state No. 1 is functional ONLY when the key is in the ON position and the vehicle gear selector is in PARK or NEUTRAL with the engine OFF. Vehicle state No. 1 is required when using OSC to carry out electrical pinpoint tests. The following transaxle components may be controlled using OSC in vehicle state No. 1.
^ SSA/SS1 - Directs PCM to command Shift Solenoid E OFF or ON
^ SSD_AMP - Controls the current to Shift Solenoid D, variable force solenoid (VFS)
^ SSC_AMP - Controls the current to Shift Solenoid C, VFS
^ SSB_AMP - Controls the current to Shift Solenoid B, VFS
^ SSA_AMP - Controls the current to Shift Solenoid A, VFS
^ TCC_AMP - Controls the current to the TCC VFS
^ PCA_AMP - Controls the current to the line pressure control (LPC) VFS
The vehicle requirements must be met when sending an OSC value to control each specific component such as the solenoids stated above. If the vehicle requirements are not met when sending the OSC value, an error message may appear. When the error message appears, OSC is cancelled and should 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 cancelled by the PCM. Use the scan tool to monitor the PID that corresponds to each OSC function or component to determine if the PCM is using the OSC value or normal control.
OSC may be cancelled at any time, using the scan tool, to return the PCM to normal control for a specific OSC function or component. See instructions for specific scan tool.
Service Bay - Vehicle State No. 2
Vehicle state No. 2 is functional ONLY when the engine is running and the vehicle gear selector is in PARK or NEUTRAL with engine speed greater than 1,100 rpm. Vehicle state No. 2 is required when using OSC to carry out a line pressure check. Most, but not all, of the solenoids may be controlled during this vehicle state. It is recommended to use vehicle state No. 1 when using OSC to control the solenoids. The following transaxle function and components may be controlled using OSC in vehicle state No. 2.
^ LINEDSD - OSC function to command line pressure to a desired pressure
^ SSD_AMP - Controls the current to Shift Solenoid D, variable force solenoid (VFS)
^ SSC_AMP - Controls the current to Shift Solenoid C, VFS
^ SSB_AMP - Controls the current to Shift Solenoid B, VFS
^ SSA_AMP - Controls the current to Shift Solenoid A, VFS
The vehicle requirements must be met when sending an OSC value to control each specific component such as the solenoids stated above. If the vehicle requirements are not met when sending the OSC value, an error message may appear. When the error message appears, OSC is cancelled and should 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 cancelled by the PCM. Use the scan tool to monitor the PID that corresponds to each OSC function or component to determine if the PCM is using the OSC value or normal control.
OSC may be cancelled at any time, using the scan tool, to return the PCM to normal control for a specific OSC function or component. See instructions for specific scan tool.
OSC values for SSA_AMP, SSB_AMP, SSC_AMP, SSD_AMP, PCA AMP and TCC AMP to control the current on the VFS solenoids are between zero (0) and one (1) amp. The following are examples.
^ 0 - Commands PCM to control current to zero amps
^ 0.25 - Commands PCM to control current to 1/4 amp or 250 milli-amps
^ 0.50 - Commands PCM to control current to 1/2 amp or 500 milli-amps
^ 0.75 - Commands PCM to control current to 3/4 amp or 750 milli-amps
^ 1 - Commands PCM to control current to 1 amp or 1,000 milli-amps
OSC will aid in testing the electronic functions of the PCM, VFS solenoid and associated circuitry. OSC allows the technician to control the PCM commanded current of the VFS solenoids and the commanded state of the on/off solenoid. This allows the technician to accurately test the electronic circuitry by comparing the commanded current with the actual current or the on/off state with the actual voltage. Shifting the transmission through the various gears tests the mechanical operation of the VFS solenoids. When using OSC to control the VFS current, the technician may measure the circuit current using an inductive pickup or measure the circuit voltage drop to help verify the proper electrical operation of each VFS solenoid.
The OSC values for LINEDSD to command a desired line pressure are between 414 kPa (60 psi) and 1,931 kPa (280 psi). The following are examples.
^ 60 psi - Commands PCM to control line pressure to 414 kPa (60 psi)
^ 100 psi - Commands PCM to control line pressure to 689 kPa (100 psi)
^ 150 psi - Commands PCM to control line pressure to 965 kPa (150 psi)
^ 200 psi - Commands PCM to control line pressure to 1,517 kPa (200 psi)
CAUTION: Do NOT command line pressure LOWER then 414 kPa (60 psi) or HIGHER then 1,931 kPa (280 psi) or damage to the transaxle can occur.
OSC allows the technician to control the PCM commanded Line Pressure. This allows the technician to accurately test the electronic pressure control system by comparing the OSC commanded line pressure to the actual line pressure indicated on the pressure gauge. The pressure gauge should be connected to the line pressure tap on the transmission. The PID corresponding to the commanded Line Pressure must be monitored to make sure the PCM is using the OSC value for the commanded Line Pressure. This test will help verify the correct operation of the transmission pump assembly, pump regulator valve and the operation of the LPC solenoid.
Drive Test
OSC allows control of 3 transmission functions while driving on the road. Each transmission function has a unique set of vehicle operating requirements that the technician is required to meet before the PCM will allow OSC to operate.
^ TCC_OSC - Commands the PCM to engage or disengage the TCC
^ GEAR_OSC - Commands the PCM to change gears (upshift or down-shift) or remain in a gear
^ HRSH_SFT - Commands a slightly higher hydraulic pressure during engagements and upshifts
The vehicle requirements must be met when sending an OSC value to control the specific functions stated above. If the vehicle requirements are not met when sending the OSC value, an error message may appear. When the error message appears, OSC is cancelled and should 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 cancelled by the PCM. Use the scan tool to monitor the PID that corresponds to each OSC function or component to determine if the PCM is using the OSC value or normal control.
OSC may be cancelled at any time, using the scan tool, to return the PCM to normal control for a specific OSC function or component. See instructions for specific scan tool.
Drive Test - Torque Converter Clutch Control
The OSC values for TCC_OSC to engage or disengage the TCC are as follows:
^ 0 - PCM in normal control of TCC and OSC is cancelled
^ 1 or OFF - Commands PCM to keep the torque converter clutch from engaging
^ 2 or ON - Commands PCM to engage the TCC using a normal ramp rate
^ 3 or ON - Commands PCM to engage the TCC using a fast ramp rate
Controlling the TCC will assist the technician in testing the operation of the torque converter for engagements and disengagements. Also, the technician may find it easier to evaluate upshifts and downshifts by first using OSC to keep the TCC from engaging.
Vehicle requirements when using TCC_OSC -Controlling the TCC.
When SENDING the TCC_OSC value [1 or OM, the engine must be running with the transaxle in the DRIVE position and the vehicle speed must be greater than 5 km/h (3 mph).
When SENDING the TCC_OSC value [2 or 3 or On the engine must be running with the selector lever in the DRIVE position, transaxle in 3rd, 4th, 5th or 6th gear, transaxle temperature between 4° C (40° F) and 121° C (250° F), the vehicle speed must be below 24 km/h (15 mph) and engine speed greater than 1,100 rpm with minimal engine load.
Drive Test - Upshift and Downshift Control
NOTE: Once OSC has successfully commanded the transmission to shift to the desired OSC gear, the transmission will remain in that gear until OSC commands a different gear or the vehicle conditions are no longer correct.
The OSC values for GEAR_OSC to control the transaxle gear changes are as follows:
^ 0 - PCM in normal shift control and OSC is cancelled
^ 1 - Commands PCM to shift to 1st gear - no engine braking
^ 2 - Commands PCM to shift to 2nd gear - with engine braking
^ 3 - Commands PCM to shift to 3rd gear - with engine braking
^ 5 - Commands PCM to shift to 5th gear - with engine braking
^ 6 - Commands PCM to shift to 6th gear - with engine braking
Controlling the gear changes will assist the technician in testing the various clutches and bands and whether the transmission is slipping in any particular gear. OSC will command the PCM to upshift or downshift depending on the OSC gear value the technician selects. The transmission will remain in the OSC gear selected until another OSC gear value is sent or until OSC is cancelled and/or the vehicle conditions for using OSC are no longer met.
Vehicle requirements when using GEAR_OSC -Controlling Gear Changes
When SENDING a GEAR_OSC value the engine must be running with the selector lever in the DRIVE position, and the vehicle speed must be greater than 5 km/h (3 mph).
Additional vehicle conditions required for upshifts:
^ Vehicle speed must be greater then 32 km/h (20 mph) when commanding an upshift to 5th or 6th gear
Additional vehicle conditions required for downshifts:
^ Vehicle speed must be less then 32 km/h (20 mph) when commanding a downshift to 1st gear
^ Vehicle speed must be less then 64 km/h (40 mph) when commanding a downshift to 2nd gear
^ Vehicle speed must be less then 97 km/h (60 mph) when commanding a downshift to 3rd gear
^ Vehicle speed must be less then 129 km/h (80 mph) when commanding a downshift to 4th gear
^ Vehicle speed must be less then 161 km/h (100 mph) when commanding a downshift to 5th gear
Drive Test - Pressure Added for Engagements and Upshifts
The OSC values for HRSH_SHFT to command a slight or moderate increase in hydraulic pressure to test for firmer engagements and upshifts are as follows:
^ 0 or OFF - PCM in normal pressure control for shifts and engagements and OSC is cancelled
^ 1 or ON - Commands PCM to moderately increase hydraulic pressure during engagements and upshifts
Setting HRSH_SFT to 1 or ON allows the technician to moderately increase the pressure when performing engagements such as P-R, P-D, N-R, N-D, R-D and when performing automatic upshifts. This can provide additional diagnostic information to help the technician determine whether the electronic pressure control system is providing at least limited control (a normal shift would become firmer). Using OSC to control HRSH_SHFT to should make a softer engagement or shift more normal and an already normal shift or engagement firmer by slightly increasing the pressure. This test should only be used to provide additional diagnostic information and should not be the only scan tool or test to determine a faulty electronic or hydraulic component.
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 that was sent. Additional PIDs are listed that may be monitored to help the technician accurately diagnose the transaxle.
The following is a list of OSC parameters and their corresponding PIDs:
