This procedure is to test validate the operation of the C1 / forward clutch control on the Toyota A750. C1 is the primary clutch that progressively engages for a N-1 shift.
This procedure presumes you are in a vehicle equipped with a CS3 connected to a Toyota A750 transmission.
- Place the vehicle in neutral or park, and turn on the vehicle power / ignition switch, but do not start the engine.
- Connect with to the CS3 with the CS Setup app.
- Navigate in the app to Diagnostics / Software Diagnostics.
- Set "Remote Mode" to "on". Wait 5 seconds.
- Turn the power / ignition switch off.
- Place the vehicle in neutral, set the parking brake, and place a foot firmly on the brake pedal.
- Start the vehicle and allow the engine to idle. The vehicle will no longer be driveable in "remote mode", but will allow manual adjustment of the shift and pressure control solenoids for this test.
- Reconnect the CS Setup app. Navigate in the app to Diagnostics / PWM Diagnostics.
- Set the transmission into the position that prepares for a shift from N to D by doing the following:
- Navigate to PWM Driver Current Command
- Set the current on PWM Driver 3 (solenoid SL1) to 1.0 A, reducing C1 pressure to minimum.
- Set the current on PWM Driver 5 (solenoid S1) to 1.0 A, turning it on.
- Set the current on PWM Driver 6 (solenoid S2) to 0.0 A, turning it off.
- Set the current on PWM Driver 7 (solenoid SR) to 1.0 A, turning it on.
- These steps will have commanded 1st gear, but with the C1 clutch completely disengaged, which is the position prior to fully engaging 1st gear.
- Move the shift lever to the D position from N. If the system is operating properly, there should be no engagement in the driveline. If there is engagement at this point, then the test has failed. Go to the After Testing steps below.
- While maintaining a firm foot on the brake pedal, select the current adjustment for PWM Driver 3 (solenoid SL1). Progressively reduce the current on PWM Driver 3 by 20 mA / .020 A at a time. If the transmission is operating properly, then at some point, the C1 clutch will start to engage, and the drivetrain will load, usually reducing engine RPM. Note the current at which engagement starts to occur. If the clutch fails to engage, then the test has failed. Go to the After Testing steps below.
- Continue reducing current until you reach 0. At this point, the C1 clutch should be fully engaged, and the vehicle should creep forward if you remove your foot from the brake pedal.
- Progressively increase current on by 50 mA until C1 disengages. The driveline should unload, and the engine idle speed may increase. If you have reached this point, the test has passed. Go to the After Testing steps below.
After you have completed the above steps, do the following:
- Leaving the vehicle running, place the vehicle back in park.
- Navigate to Diagnostics / Software Diagnostics
- Set "Remote Mode" to "off". Wait 5 seconds.
- Turn the power / ignition switch off. The vehicle should drive normally again on the next startup.
- Report the test results, including the PWM Driver 3 current where C1 started to engage.