OSC For Transmission - Service Bay Mode

The Service Bay Mode is used to test various transmission components and functions when the vehicle is in the service bay. The Service Bay Mode is used when carrying out electrical pinpoint tests and hydraulic pressure tests. Each OSC function has a unique set of vehicle operating requirements or vehicle states that the technician is required to meet before the PCM will allow the OSC to operate. The Service Bay Mode is used in the following 3 vehicle states:

Vehicle State No. 1

• The Vehicle State No. 1 requirements for sending an OSC value as follows:
  • Key ON
  • Engine not running
  • Gear selector in PARK or NEUTRAL

Vehicle State No. 1 is used when carrying out electrical pinpoint tests. The following transmission components may be controlled using the OSC in Vehicle State No. 1:

• SSE_AMP - Controls the current to the SSPC-E (low and reverse clutch) solenoid.
• SSD_AMP - Controls the current to the SSPC-D (direct clutch) solenoid.
• SSC_AMP - Controls the current to the SSPC-C (intermediate clutch) solenoid.
• SSB_AMP - Controls the current to the SSPC-B (overdrive clutch) solenoid.
• SSA_AMP - Controls the current to the SSPD-A (coast clutch) solenoid.
• TCC_AMP - Controls the current to the torque converter clutch (TCC) solenoid.
• LINEDSD - Controls the commanded pressure, which in turn controls the current to the PC-A (line pressure control) solenoid.

The vehicle requirements must be met when sending the OSC value for SSPC-E, SSPC-D, SSPC-C, SSPC-B, SSPC-A, TCC and PC-A solenoids. If the vehicle requirements are not met when sending the OSC value, an error message may appear. When the error message is received, the 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 (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel the OSC.

Vehicle State No. 2

• The Vehicle State No. 2 requirements for sending an OSC value are as follows:
  • Engine running
  • Exception: Engine running greater than 1,000 RPM to control LINEDSD
  • Gear selector in PARK or NEUTRAL

Vehicle State No. 2 is used when carrying out electronic pressure control tests and electrical pinpoint tests. The following transmission components may be controlled using the OSC in Vehicle State No. 2:

• SSE_AMP - Controls the current to the SSPC-E (low and reverse clutch) VFS solenoid.
• SSB_AMP - Controls the current to the SSPC-B (overdrive clutch) solenoid.
• SSA_AMP - Controls the current to the SSPC-A (coast clutch) solenoid.
• TCC_AMP - Controls the current to the TCC solenoid.
• LINEDSD - Controls the commanded pressure, which in turn controls the current to the PC-A (line pressure control) solenoid.

The vehicle requirements must be met when sending the OSC value for SSPC-E, SSPC-B, SSPC-A, TCC and PC-A solenoids. If the vehicle requirements are not met when sending the OSC value, an error message may appear. When the error message is received, the 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 (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.

Vehicle State No. 3

• Vehicle State No. 3 requirements for sending an OSC value are as follows:
  • Engine running
  • Gear selector in overdrive
  • Vehicle not moving

Vehicle State No. 3 is used when carrying out electronic pressure control tests and electrical pinpoint tests. The following transmission components may be controlled using the OSC in Vehicle State No. 3:

• SSD_AMP - Controls the current to the SSPC-D (direct clutch) solenoid.
• SSC_AMP - Controls the current to the SSPC-C (intermediate clutch) solenoid.

The vehicle requirements must be met when sending the OSC value for SSPC-D and SSPC-C solenoids. If the vehicle requirements are not met when sending the OSC value, an error message may appear. When the error message is received, the 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 (monitor corresponding PID). The OSC value XXX may be sent anytime to cancel OSC.

The OSC options to control SSA_AMP, SSB_AMP, SSC_AMP, SSD_AMP, SSE_AMP, TCC_AMP for solenoids in Service Bay Mode are as follows:

• 0 - Commands PCM to control current to zero amps.
• 0.25 - Commands PCM to control current to 1/4 amp to 250 milliamps.
• 0.50 - Commands PCM to control current to 1/2 amp or 500 milliamps.
• 0.75 - Commands PCM to control current to 3/4 amp or 750 milliamps.
• 1.0 - Commands PCM to control current to 1 amp or 1,000 milliamps.
• XXX - Cancels OSC and allows the PCM normal control of the VFS solenoids.

Controlling the solenoids allows the technicians to measure the circuit current using an inductive pickup or to measure the circuit voltage when carrying out electrical tests.

The OSC options to control LINEDSD for line pressure in Service Bay Mode are as follows:

• 20 - Commands PCM to control line pressure to 20 psi.
• 60 - Commands PCM to control line pressure to 60 psi.
• 100 - Commands PCM to control line pressure to 100 psi.
• 140 - Commands PCM to control line pressure to 140 psi.
• 180 - Commands PCM to control line pressure to 180 psi.
• 220 - Commands PCM to control line pressure to 220 psi.
• 260 - Commands PCM to control line pressure to 260 psi.
• 300 - Commands PCM to control line pressure to 300 psi.
• XXX - Cancels OSC and allows the PCM normal control of the line pressure.

The OSC allows the technician to control the commanded line pressure instead of the PC-A current. The PCM will command a specific current to the PC-A solenoid when requesting a particular OSC line pressure. Using OSC to control the line pressure allows the technician to accurately test the electronic pressure control system by comparing the OSC command line pressure to the actual line pressure indicated on the gauge. This will aid in testing for pump capacity and the ability of the PCM to electronically control the pressure. The technician may also measure the circuit current using an inductive pickup or to measure the circuit voltage when carrying out an electrical test on the line pressure (PC-A) solenoid.