P0741

Diagnostic Chart:

Schematic:

Circuit Description with 4L80-E / 4L85-E Automatic Transmission

IMPORTANT: DTC P0741 inspects for high Torque Converter Clutch (TCC) Slip In 2nd And 3rd Gear Only. The Transmission Must Be In Hot Mode or experiencing a wide open throttle maneuver in order for the TCC to be commanded ON in 2nd and 3rd gear.

The Powertrain Control Module (PCM) energizes the Torque Converter Clutch Pulse Width Modulated (TCC PWM) solenoid valve by grounding circuit 418. This blocks the exhaust for TCC signal fluid and allows filtered 2-3 drive fluid to feed the TCC signal circuit. When the vehicle's operating conditions are appropriate for TCC application, the PCM begins the TCC duty cycle to approximately 30%. 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%, 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% to achieve full apply pressure, in the regulated apply fluid circuit. The TCC PWM solenoid valve is de-energized by the PCM opening circuit 418. 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 B DTC.

CONDITIONS FOR RUNNING THE DTC
^ The system voltage is 8.0-18.0 volts.
^ The engine speed is greater than 475 RPM for greater than 7 seconds.
^ No OSS DTCs P0722 or P0723.
^ No 185 DTCs P0716 or P0717.
^ No TFP manual valve position switch DTCs P1810, P1815, P1816, P1817 or P1818.
^ No TCC PWM electrical DTC P1860.
^ No TCC Stuck ON DTC P0742.
^ TCC on time is greater than 1.0 second.
^ TCC duty cycle is greater than 70%.
^ No TFP manual valve position switch change for greater than 4 seconds.
^ TFP manual valve position switch indicates D4, D3 or D2.
^ TFT is 20-149°C (68-300°F).
^ The APP angle is greater than 10%.
^ The engine torque is 140-675 N.m (100-500 lb ft).
^ Gear ratio is 1.50-1.45 or 1.05-0.95.

CONDITIONS FOR SETTING THE DTC
^ TCC slip is greater than 140 RPM.
^ All conditions for running the DTC are met for 3 seconds for 5 occurrences.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL).
^ The PCM inhibits the TCC.
^ The PCM increases line pressure.
^ The PCM inhibits 4th gear.
^ The PCM stores DTC P0741 in PCM history.

CONDITIONS FOR CLEARING THE MIL/DTC
^ For Federal and California emissions, the PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ A scan tool clears the DTC from PCM history.
^ For Federal and California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without an emission related diagnostic fault occurring.
^ For vehicles equal to or greater than 15,000 lbs GVW, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without a non-emission related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS
^ Residue or contamination may cause shift valves to stick intermittently.
^ First, diagnose and clear any engine DTCs or TP sensor codes that are present. Then inspect for any transmission DTCs that may have reset.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests for excessive TCC slip when TCC is commanded on.
3. This step inspects for possible causes of no TCC apply.