Circuit Description
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 C DTC. For California emissions vehicles DTC P0741 is a type B DTC.
Conditions for Running the DTC
| • | No TP sensor DTCs P0121, P0122, or P0123. |
| • | No OSS DTCs P0502, or P0503. |
| • | No ISS DTCs P0716 or P0717. |
| • | No TCC DTCs P0742 or P1860. |
| • | No TFP manual valve position switch DTC P1810. |
| • | The engine must be running greater than 300 RPM for at least 7 seconds. |
| • | The gear ratio must indicate 2nd, 3rd, or 4th gear. |
| • | The TP is 10-100%. |
| • | The TFP manual valve position switch must be in D4, D3, or D2 and has not changed in 6 seconds. |
| • | The system voltage is 8.0-18.0 volts. |
| • | Gear ratio is equal to 2nd, 3rd or 4th. |
| • | The transmission fluid temperature (TFT) is 20-150°C (68-302°F). |
| • | TCC duty cycle greater than 75% and locked on greater than 0.75 seconds. |
Conditions for Setting the DTC
| • | The TCC slip speed is greater than 130 RPM, for 3.5 seconds. |
| • | All conditions must be met for a total of 5 occurrences. |
Action Taken When the DTC Sets
| • | For California emission equipped vehicles, the PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. For Non-California emission equipped vehicles, the malfunction indicator lamp (MIL) is not illuminated. |
| • | The PCM inhibits the TCC. |
| • | The PCM increases line pressure. |
| • | The PCM inhibits 4th gear if TFT is greater than 130°C (266°F). |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame (Calif. only) and Failure Records (Calif. and Federal). |
| • | The PCM stores the DTC P0741 in PCM history during the second consecutive trip (Calif.) or the first trip (Federal) in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | For California emissions, the PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
| • | A scan tool can clear the MIL/DTC. |
| • | For 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 Federal emissions, 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
| • | First diagnose and clear any engine DTCs or TP sensor codes that are present. Then inspect for any transmission DTCs that may have reset. |
| • | Residue or contamination may cause shift valves to stick intermittently. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for excessive TCC slip when TCC is commanded on.
-
This step inspects for possible causes of no TCC apply.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain Diagnostic System Check? | -- | ||||||||||
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM. Is the TCC slip speed snapshot data greater than the specified value when the TCC duty cycle is commanded greater than 70% for greater than 3 seconds? | 140 RPM | Go to Diagnostic Aids | ||||||||||
Inspect the TCC PWM solenoid valve for being mechanically Stuck OFF. Refer to Torque Converter Diagnosis . Did you find and correct the condition? | -- | |||||||||||
4 |
Refer to Symptom Diagnosis No TCC Apply. Did you find and correct the condition? | -- | -- | |||||||||
5 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
