DTC P0742 TCC System Stuck On 3.8L
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The torque converter
clutch (TCC) solenoid valve is a normally-open exhaust valve that is used with
the torque converter clutch pulse width modulation (TCC PWM) solenoid
valve in order to control fluid acting on the converter clutch apply valve. The
TCC solenoid valve attaches to the transmission case assembly extending into
the pump cover. When grounded (energized) by the powertrain
control module (PCM), the TCC solenoid valve stops converter signal oil from
exhausting. This causes converter signal oil pressure to increase and move the
converter clutch apply valve against spring force and into the apply position.
In this position, release fluid is open to an exhaust port and converter feed
fluid fills the apply fluid circuit. The converter
feed fluid applies the TCC. When the PCM no longer provides a ground path, the
TCC solenoid valve de-energizes and apply fluid
exhausts, releasing the TCC.
When the PCM detects low
torque converter slip when the PCM commands the TCC OFF, then DTC P0742
sets. DTC P0742 is a type B DTC.
for Running the DTC
- No MAF sensor DTCs P0101, P0102 or
- No MAP sensor DTCs P0107 or P0108.
- No TP sensor DTCs P0122 or P0123.
- No VSS assembly DTCs P0502 or P0503.
- No TCC solenoid valve
- No TFP manual valve position switch DTC P1810.
- No TCC PWM solenoid valve
- The TP angle is 13-99%.
- The engine speed is greater than
450 RPM for 5 seconds.
- The engine is not in fuel cutoff.
- The engine torque is
50-400 lbs ft.
- The engine vacuum is 0-105 kPa.
- The engine speed is
- The speed ratio is 0.95-1.7 (the
speed ratio is engine speed divided by output speed).
- The vehicle speed is
32-120 km/h (20-75 mph).
- The commanded gear is not 1st.
- The gear range is D4.
- The gear range does not change
within 6 seconds.
- The TCC is commanded OFF.
for Setting the DTC
DTC P0742 sets if
the following condition occurs three times.
The TCC slip speed is
-20 to +50 RPM for 3.8 seconds.
Taken When the DTC Sets
- The PCM illuminates the malfunction
indicator lamp (MIL) during the second consecutive trip in which the
Conditions for Setting the DTC are met.
- The PCM freezes shift adapts from
- The PCM records the operating
conditions when the Conditions for Setting the DTC are met. The PCM stores
this information as Freeze Frame and Failure Records.
- The PCM stores DTC P0742 in PCM
history during the second consecutive trip in which the Conditions for
Setting the DTC are met.
for Clearing the MIL/DTC
- 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.
- The PCM clears the DTC from PCM
history if the vehicle completes 40 warm-up cycles without an
emission-related diagnostic fault occurring.
- The PCM cancels the DTC default
actions when the fault no longer exists and/or the ignition switch is OFF
long enough in order to power down the PCM.
The TCC fluid
hydraulically applies the TCC, possibly causing an engine stall, under the
- The TCC is hydraulically stuck ON
- The parking brake is applied
- Any gear range is selected
The numbers below refer
to the step numbers on the diagnostic table.
- This step tests the
hydraulic state of the TCC. When the PCM commands the TCC solenoid valve
OFF, the slip speed should increase.
DTC P0742 TCC System Stuck On (3.8L)
you perform the Powertrain Diagnostic System Check?
to Step 2
Go to A
Powertrain On Board Diagnostic (OBD) System Check
in Engine Controls
- Install a Scan Tool
- Turn ON the ignition, with the
clearing the DTC, 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.
- Record the DTC Freeze Frame and
- Clear the DTC.
- Drive the vehicle in the D4 drive
range in second, third or fourth gear under steady acceleration, with a
TP angle greater than 20%.
the Scan Tool
TCC Enable status is No, does the Scan Tool
display a TCC Slip Speed within the specified range?
-20 to +50 RPM
to Step 3
Go to Diagnostic Aids
TCC is hydraulically stuck ON. Inspect for the following conditions:
- A clogged exhaust orifice in the
TCC solenoid valve.
- The converter clutch apply valve
is stuck in the apply position.
- A misaligned or damaged valve body
- A restricted release passage.
- A restricted transmission cooler
you find and correct the condition?
to Step 4
the following procedure in order to verify the repair:
- Select DTC.
- Select Clear Info.
- Drive the vehicle in D4 under the
following conditions: Hold the throttle at 25% and accelerate to
88 km/h (55 mph). Ensure that the Scan Tool
TCC Slip Speed is 100 to +2000 RPM for 2 seconds, with the TCC
- Select Specific DTC.
- Enter DTC P0742.
the test run and passed?
to Step 1