DTC P0741 or P0742
Diagnostic Instructions
DTC Descriptors
DTC P0741: Torque Converter Clutch (TCC)
System Stuck Off
DTC P0742: Torque Converter Clutch (TCC)
System Stuck On
Circuit/System Description
The torque converter clutch (TCC) pressure
control (PC) solenoid is part of the control solenoid valve
assembly which has no serviceable components. The TCC PC solenoid
is a normally low pressure control solenoid. The TCC PC
solenoid regulates transmission fluid pressure to the TCC regulator
valve in the lower valve body and the TCC control valve in the
fluid pump assembly. When vehicle operating conditions are
appropriate to apply the torque converter clutch, the transmission
control module (TCM) will increase TCC PC current
flow (duty cycle) thereby increasing pressure to move the TCC
control valve into the apply position. When the TCC is fully
applied, the engine is coupled directly to the transmission. TCC
release is accomplished by the TCM decreasing current flow,
dropping the apply pressure thereby allowing the TCC control valve
to move to the release position. The TCM calculates torque
converter slip speed based on the RPM signal from the input speed
sensor (ISS) and engine RPM provided by the engine control
module (ECM).
Conditions for Running the DTC
P0741
• |
DTC P0101, P0102, P0103, P0106, P0107, P0108,
P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205,
P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305,
P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723,
P0741, P0742, P2763, or P2764 is not set. |
• |
The engine speed is greater than 400 RPM for
5 seconds. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
The transmission fluid temperature (TFT) is
between -7 to +130°C (19-266°F). |
• |
The throttle position is 8 percent or
greater. |
• |
The engine torque is 50 N·m
(36 lb ft) or greater. |
• |
The 2nd gear ratio is between 2.75-3.17. |
• |
The 3rd gear ratio is between 1.78-2.04. |
• |
The 4th gear ratio is between 1.35-1.55. |
• |
The 5th gear is between 0.93-1.07. |
• |
The 6th gear is between 0.70-0.80. |
• |
The TCC is commanded ON. |
• |
The engine torque signal is valid. |
• |
The throttle position signal is valid. |
P0742
• |
DTC P0101, P0102, P0103, P0106, P0107, P0108,
P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205,
P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305,
P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723,
P0741, P0742, P2763, or P2764 is not set. |
• |
The engine speed is greater than 400 RPM for
5 seconds. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
The TFT is 20-130°C (68-266°F). |
• |
The calculated throttle position is greater than
8 percent. |
• |
The engine torque is greater than
80 N·m (59 lb ft). |
• |
The vehicle speed greater than 16 km/h
(10 mph). |
• |
Commanded gear is 2nd or greater. |
• |
The gear ratio is between 0.69-1.97. |
Conditions for Setting the DTC
P0741
The TCM detects TCC slip greater than 150 RPM for
5 seconds with a TCC commanded ON pressure of 500 kPa or
greater. This must occur 6 times during the same ignition
cycle.
P0742
The TCM detects the TCC slip is between -20 and +30 RPM for
1.2 seconds or greater when the TCC is commanded OFF
5 times during the same ignition cycle.
Action Taken When the DTC Sets
P0741
• |
DTC P0741 is a Type B DTC. |
• |
The TCM inhibits top gear. |
• |
The TCM initiates the Hot Mode shift pattern. |
• |
The TCM commands the TCC OFF. |
P0742
• |
DTC P0742 is a Type A DTC. |
• |
The TCM initiates Hot Mode shift pattern. |
• |
The TCM freezes transmission adaptive
functions. |
• |
The TCM commands the TCC ON. |
Conditions for Clearing the DIC/DTC
P0741
DTC P0741 is a Type B DTC.
P0742
DTC P0742 is a Type A DTC.
Diagnostic Aids
When attempting to set transmission performance DTCs, observe
the Freeze Frame and Failure Records to assist in duplicating the
failure conditions. Ensure the transmission fluid level is correct
and there are no leaks.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Perform the
Transmission Fluid Level and Condition Check to verify correct
fluid level and condition.
- Engine ticking over in Park, verify with a scan tool
the transmission ISS/OSS Supply Voltage parameter displays OK.
- Engine ticking over in Park, observe the Transmission
ISS parameter on the scan tool, while varying the engine speed. The
Transmission ISS parameter should vary with engine speed and not
drop out.
Note: Perform a scan tool
snapshot during the road test.
- Perform the
Road Test . Verify the transmission operation performs as
indicated in the road test instructions.
- Review the snapshot transmission data parameters.
Verify the engine and transmission data parameters display the
correct values in all forward gear ranges.
• |
Engine Coolant Temperature |
• |
Transmission Fluid Temperature |
• |
TCC Pressure Control Solenoid Valve Pressure
Command |
- After performing the above steps, verify that the DTC
does not reset by operating the vehicle within the Conditions for
Running the DTC. You may also operate the vehicle within the
conditions you observe from the Freeze Frame/Failure Records data.
If the vehicle passes the Circuit/System Verification procedure,
then STOP. Do not perform the Circuit/System Testing or Component
Testing as this may result in an unnecessary part replacement.
Refer to
Testing for Intermittent Conditions and Poor Connections .
Circuit/System Testing
- Perform the
Line Pressure Check . Verify the transmission line pressures
are within the range specified in the Line PC Solenoid Valve
Pressure table. Refer to
Solenoid Valve Pressure .
- Ignition OFF, remove the Q8 control solenoid valve
assembly. Refer to
Control Solenoid Valve and Transmission Control Module Assembly
Replacement .
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly
Solenoid Performance Test .
⇒ |
If the Q8 control solenoid valve assembly does not
pass the test, replace the Q8 control solenoid valve assembly. |
- Listed in the table below are conditions for each
component that could set a DTC P0741 or P0742. Carefully
inspect each component for that condition. Repair or replace as
necessary.
DTCs
|
Component
|
Condition
|
P0741
P0742
|
Upper Valve Body
|
TCC Control Valve
• |
Stuck TCC control valve |
|
P0741
P0742
|
Upper Valve Body
|
TCC Regulator Valve
• |
Stuck TCC regulator valve |
|
P0741
P0742
|
Q8 Control Solenoid Valve Assembly
|
TCC Pressure Control Solenoid
• |
Not pressurising - Stuck OFF or leaking |
• |
Not exhausting - Stuck ON |
• |
Control signal fluid supply leak - valve body
filter plate assembly cracked, or damaged gasket seal |
|
P0741
|
Torque Converter
|
• |
Torque converter clutch delamination or material
worn off |
• |
Converter bolts too long damaging the clutch apply
surface |
|
P0741
|
Support
|
Damaged seal
|
P0741
P0742
|
A/Transfer case Cover (403)
|
Release Blow-off
|
P0741
|
Upper Valve Body
|
Release exhaust port/orifice plugged or blocked
|
P0741
|
Turbine Shaft
|
Turbine shaft O-ring seal cut or damaged
|
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|