The transmission control module (TCM) controls the TCC pressure control solenoid valve pulse width modulation. When the solenoid is commanded on, it exhausts release oil and allows regulated apply oil to flow to the apply circuit of the TCC system. The pressure in this system applies the pressure plate to the converter housing, and couples the transmission and engine directly through the TCC. The TCC slip speed should be near zero when fully applied.
At start-up with the vehicle in park, the TCC slip speed is sampled. If the slip speed is less than a calibrated value, a fail counter is incremented.
When the TCM detects that a certain percentage of the TCC slip speed samples have failed when the TCC is commanded OFF in park, DTC P0742 sets. DTC P0742 is a type B DTC.
• | No engine torque DTC P1779. |
• | No OSS DTCs P0722, or P0723. |
• | No ISS DTCs P0716 or P0717. |
• | No TCC system stuck OFF DTC P0741. |
• | No transmission range switch DTCs P0705, P1756, or P1758. |
• | No TCC enable solenoid valve DTCs P1888 or P1889. |
• | The ignition voltage is 8-18 volts. |
• | The engine speed is 500-2000 RPM. |
• | The selected range is PARK. |
• | The transmission fluid temperature is greater than 20°C (68°F). |
• | The APP angle is less than 3 percent. |
• | The change in throttle position angle is 2 percent or less since start-up. |
Eighty percent of the TCC slip speed samples are less than 3 RPM.
• | The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The TCM commands full TCC engagement when output shaft speed is above 500 RPM. |
• | The TCM commands maximum pressure to the input clutch. |
• | The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records. |
• | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records. |
• | The TCM stores DTC P0742 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request. |
• | A scan tool can clear the MIL/DTC. |
• | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring. |
• | The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM. |
• | The customer may notice an engine stalling condition. |
• | An intermittent stuck TCC control valve and/or TCC regulator valve can cause DTC P0742 to set. |
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.2 (L61) | ||||||||||||||
2 |
Important:
Is the TCC Slip Speed within the specified range? | -3 to +3 RPM | Go to Step 3 | Go to Intermittent Conditions in Engine Controls - 2.2L (L61) | ||||||||||||||
Inspect for the following conditions:
Refer to Control Valve Body Assembly Disassemble . Did you find and correct any of the above conditions? | -- | Go to Step 4 | -- | |||||||||||||||
4 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 5 | Go to Step 2 | ||||||||||||||
5 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 2.2L (L61) | System OK |