Circuit Description

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: DTC P0741 detects high torque converter clutch (TCC) slip speed in commanded 2nd and 3rd gears only. TCC is only commanded on in these gears during hot mode, wide open throttle (WOT), or if the gear selector indicates Drive 3 or Drive 2.

The powertrain control module (PCM) energizes the torque converter clutch pulse width modulated (TCC PWM) solenoid valve by closing the control circuit. This blocks the exhaust for TCC signal fluid and allows filtered 2-3 drive fluid to feed the TCC signal circuit. When the vehicle operating conditions are appropriate for TCC application, the PCM increases the TCC duty cycle to approximately 30 percent. This allows TCC signal fluid pressure to move the converter clutch shift valve into the apply position and direct regulated apply fluid to the torque converter. The PCM then increases, ramps, the duty cycle to approximately 60 percent, where regulated apply fluid pressure, applies the converter clutch. The vehicle application determines the TCC apply rate. Once the TCC applies, the duty cycle immediately increases to approximately 70 percent to achieve full apply pressure, in the regulated apply fluid circuit.

The TCC PWM solenoid valve is de-energized by the PCM opening the control circuit. This action allows the TCC signal fluid to exhaust through the solenoid and blocks filtered 2-3 drive fluid from entering the TCC signal circuit. The loss of fluid pressure in the TCC signal circuit releases the TCC.

If the PCM detects high TCC slip when the TCC is commanded ON, then DTC P0741 sets. DTC P0741 is a type C DTC. For California emissions vehicles DTC P0741 is a type B DTC.