Torque Converter Clutch (TCC) Solenoid

The torque converter clutch pulse width modulated (TCC PWM) solenoid is a normally-closed solenoid used to control the apply and release of the converter clutch. When the vehicle operating conditions are appropriate to apply the TCC, the transmission control module (TCM) immediately increases the duty cycle to approximately 42 percent. The TCM then ramps the duty cycle to approximately 90 percent to achieve full TCC apply pressure. When the TCC is fully applied, the engine is coupled directly to the transmission through the TCC. The TCM normally allows a small amount of slip to occur. When the TCC is engaged, TCC slip speed is maintained at approximately 20-50 RPM.

1-2 Shift Solenoid and 2-3 Shift Solenoid

The 1-2 shift solenoid (SS) valve and the 2-3 SS valve controls transmission fluid pressure acting on the shift valves to position the valves for the appropriate gear. The 1-2 SS and the 2-3 SS valves are normally-open exhaust valves located on the control valve body. A fused circuit supplies ignition voltage to the 1-2 SS valve and the 2-3 SS valve. The TCM commands the solenoid ON or OFF by switching the ground path. The TCM identifies a 1-2 SS valve or a 2-3 SS valve condition by monitoring the commanded gear versus gear ratio.

Condition 1

Condition 2

DTC P0894 is a type B DTC.

DTC P0894 is a type B DTC.

If the DTC is cleared, then will not set again when the vehicle is driven, some of the following conditions may exist:

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Perform the Transmission Fluid Check .

⇒	Correct the transmission fluid level if the fluid is not at the proper level.

2. Using the scan tool, clear the DTC. If DTC P0894 was set, operate the vehicle greater than 72 km/h (45 mph) and use the scan tool to command the TCC ON. Observe the TCC Slip Speed parameter on the scan tool. The TCC Slip Speed should be below 125 RPM.

⇒	If the TCC Slip Speed is greater than 125 RPM, inspect the following components and repair or replace as necessary:

•	The cooling system for plugging

•	The cooling lines may be pinched

•	The TCC control valve for sticking

•	The TCC regulator valve for sticking

•	The pressure regulator valve

•	The TCC PWM solenoid valve stuck and O-ring seal for leaks

•	The TCC blowoff valve or spring for damage or not seating

•	The TCC signal orifice in the spacer plate plugged

•	The #1 check ball missing or leaking

•	The spacer plate gaskets torn or leaking

•	The turbine shaft seals for leaks

•	The torque converter clutch

3. Using the scan tool, clear the DTC. If DTC P0894 is set, drive the vehicle to ensure the TCM commands 1st, 2nd, 3rd, and 4th gear. The ratios should match the commanded gear for all gears.

⇒	If the gear ratios do not match the commanded gear, inspect the following and repair or replace as necessary:

•	The 1-2 SS mechanically stuck

•	The 2-3 SS mechanically stuck

•	A stuck or binding 1-2 shift valve

•	A stuck or binding 2-3 shift valve

•	Damaged seals on the shift solenoid valve

1. Perform the Shift Solenoid Leak Test .

⇒	If the solenoid fails the shift solenoid leak test, replace the affected solenoid.

2. Disconnect the wiring harness connector from the affected solenoid. Measure the resistance for the affected solenoid. The resistance should be between 19 and 31 ohms for the 1-2 SS and the 2-3 SS. The resistance should be between 10 and 15 ohms for the TCC solenoid.

⇒	If the resistance is not within the specified range, replace the affected solenoid.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.