4L80-E / 4L85-E Automatic Transmission
DTC P2761
Circuit Description
The torque converter clutch pulse width modulation (TCC PWM) solenoid valve controls fluid acting on the converter clutch valve, which controls TCC apply and release. The TCC PWM solenoid valve attaches to the control valve body within the transmission. Ignition voltage goes directly to the TCC PWM solenoid valve. The powertrain control module (PCM) controls the TCC PWM solenoid valve by providing a ground path on the control circuit. The current flows through the TCC PWM solenoid valve coil according to the duty cycle, percentage of ON time. The TCC PWM solenoid valve provides a smooth engagement of the torque converter clutch by operating on a duty cycle percent of ON time.
If the PCM detects a continuous open or short in the TCC PWM solenoid valve circuit or the TCC PWM solenoid valve, then DTC P2761 sets. DTC P2761 is a type C DTC. For California emission vehicles and vehicles under 8,600 GVW, DTC P2761 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2761 Torque Converter Clutch (TCC) Pressure Control (PC) Solenoid Control Circuit
Conditions for Running the DTC
The engine is running for greater than 7 seconds.
Conditions for Setting the DTC
One of the following conditions occur for 4.3 out of 5 seconds.
^ The PCM commands the TCC PWM solenoid valve to OFF, 0 percent, and the voltage input remains low, zero volts.
^ The PCM commands the TCC PWM solenoid valve to ON, 100 percent, and the voltage input remains high, B+.
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.
^ The PCM inhibits TCC engagement.
^ The PCM commands increased line pressure.
^ The PCM freezes transmission adaptive functions.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame, California only, and Failure Records, California and Federal.
^ The PCM stores DTC P2761 in PCM history.
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 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 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
DTC P2761 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
4. This step tests for voltage to the solenoid.
5. This step tests the ability of the PCM and wiring to control the ground circuit.
7. This step tests the resistance of the TCC PWM solenoid valve and the automatic transmission wiring harness assembly.
Step 1 - Step 9:
Step 10 - Step 18:
