Circuit Description
The Torque Converter Clutch Solenoid Valve (TCC Sol. Valve) is a pulse
width modulated solenoid. When vehicle operating conditions are appropriate
for TCC application, the Powertrain Control Module (PCM) begins the TCC duty
cycle at approximately 42%. The PCM then increases the duty cycle up to 90%,
in order to achieve full TCC-apply pressure.
When the TCC Sol. Valve is de-energized, the solenoid blocks filtered
2-3 drive fluid, and allows TCC signal fluid to exhaust. When energized, the
solenoid modulates fluid into the TCC signal fluid circuit. When fully energized,
modulation stops, and the solenoid blocks both 2-3 drive fluid and TCC signal
fluid exhaust.
When the PCM detects a high TCC slip speed when the TCC is commanded
ON, then DTC P0741 sets. DTC P0741 is a type B DTC.
Conditions for Setting the DTC
| • | No TP DTCs P0121, P0122 or P0123. |
| • | No VSS DTCs P0502 or P0503. |
| • | No TCC Stuck ON DTC P0742. |
| • | No TFP Val. Position Sw. DTC P1810. |
| • | No TCC Release Sw. DTC P1887. |
| • | The time since the gear select lever change is greater than 6 seconds. |
| • | The TFP Val. Position Sw. indicates 2, 3, or D. |
| • | The PCM commands the TCC ON for greater than 3 seconds. |
| • | The transmission fluid temperature (TFT) is 20-130°C
(68-266°F). |
| • | The commanded gear is 4th. |
| • | The TCC slip speed is greater than 250 RPM for 8 seconds,
two consecutive times. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | The PCM inhibits TCC engagement. |
| • | The PCM freezes shift adapts from being updated. |
| • | DTC P0741 is stored in the PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive trips
without a failure reported. |
| • | A scan tool can clear the DTC from the PCM history. The PCM clears
the DTC from the PCM history if the vehicle completes 40 warm-up cycles without
a failure reported. |
| • | The PCM cancels the DTC default actions when the fault no longer
exists and the ignition is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | Inspect the transmission fluid level. |
| • | The transmission may be in Hot Mode. Inspect the transmission
fluid lines to the radiator. The lines may be pinched, plugged or twisted. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step inspects the transmission fluid to ensure that it is at the
proper level.
-
This step verifies that the TCC engages when commanded
ON by the scan tool.
DTC P0741 Torque Converter Clutch System -- Stuck Off
Step
| Action
| Value(s)
| Yes
| No
|
1
| Was the Powertrain On-Board Diagnostic (OBD) System Check
performed?
| --
|
Go to Step
2
| Go to
Powertrain On Board Diagnostic (OBD) System Check
|
2
| Have you performed the transmission fluid
checking procedure?
| --
|
Go to Step 3
| Go to
Transmission Fluid Check
|
3
|
- Install the Scan Tool
.
- With the engine OFF, turn the ignition switch to the RUN position.
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze
Frame and Failure Records for reference. Using the Clear Info function will
erase the stored Freeze Frame and Failure Records from the PCM.
- Record the DTC Freeze Frame and Failure Records, then clear the DTCs.
- Drive the vehicle at 72 km/h (45 mph).
- Using the scan tool, command the TCC Solenoid ON.
- Monitor the TCC slip speed.
Is the slip speed less than the specified value?
| 100 RPM
| Go to Diagnostic Aids
|
Go to Step
4
|
4
| Inspect and repair as necessary
the following items:
| • | The TCC PWM Sol. Valve O-ring for leaks or cuts. |
| • | The TCC PWM Sol. Valve for the filter being clogged. |
| • | The TCC Control Valve for being stuck in the TCC release position. |
| • | The TCC Regulated Apply Valve for being stuck in the TCC release
position. |
| • | The TCC Feed Limit Valve for being stuck due to sediment or binding. |
| • | The Pressure Regulator Valve for being stuck due to sediment or
binding. |
| • | The TCC fluid circuits for leaks. |
| • | The turbine shaft seals for leaks or cuts. |
| • | The torque converter for ballooning. |
Refer to Unit Repair.
Is the inspection and repair complete?
| --
|
Go to Step 5
| --
|
5
| In order to verify your repair, perform the following procedure:
- Select DTC.
- Select Clear Info.
- Operate the vehicle under the following conditions:
| • | Drive the vehicle in D4 with the throttle greater than 8%. |
| • | Obtain 72 km/h (45 mph). |
| • | With the TCC commanded ON and engaged, the slip speed must be
less than 50 RPM for 3 seconds. |
- Select Specific DTC. Enter DTC P0741.
Has the test run and passed?
| --
| System OK
|
Begin the diagnosis again. Go to Step 1
|
