Technical Description of OBD-II Trouble Code
Low Circuit in Torque Converter Clutch
This powertrain code (DTC) is a generic OBD-II code that applies to all vehicle makes and models (1996-newer). However, the specific repair steps may vary depending on the model.
What does that mean?
Modern vehicles with automatic transmissions use a torque converter to increase engine torque output and drive the rear wheels. The torque converter is a fluid coupling mechanism that multiplies torque until the speeds equalize and create a “stall” speed. Torque converter clutch (TCC) solenoids, commanded by the Powertrain Control Module (PCM) or Transmission Control Module (TCM), engage the torque converter clutch to increase efficiency.
The transmission control module has detected a fault in the circuit that operates the torque converter clutch solenoid. For the purpose of this article, we will consider the TCM as the controller, although it may be controlled through the PCM. Consult factory wiring diagrams to determine which system is being used.
Note: This code is similar to codes P0740, P0741, P0742, P0743, P0744, and P2770.
A P2769 code means that the PCM has detected a low condition in the TCC electrical circuit. There may be other diagnostic trouble codes associated with the transmission control module that can only be accessed with an advanced scan tool. If any additional transmission-related DTCs appear along with P2769, an electrical failure is likely.
Symptoms
Symptoms of a P2769 trouble code may include:
Potential Causes
Possible causes of this DTC may include:
Diagnostic Steps for P2769 DTC
Wiring harness – Check the transmission wiring harness for damage or loose connections. Use a factory wiring diagram to locate the appropriate power source and connection points between circuits. The transmission may be powered by a fuse or relay and triggered by the TCM. Disconnect the transmission harness at the transmission connector, power source, and TCM. Check for continuity inside the transmission internal wiring harness by locating the appropriate + and – pins for the torque converter clutch solenoid.
Using a digital volt ohm meter (DVOM) set to the ohms scale, check for resistance in the circuit with the positive and negative leads on the appropriate pins. If the resistance is extremely high or over the limit (OL), suspect a fault with the internal harness or the TCC solenoid. Removing the transmission oil pan may be necessary to further diagnose the TCC solenoid.
Test the wiring between the TCM and the wiring harness connector at the transmission case using the DVOM set to the ohms scale. Check for a possible short to ground by moving the negative lead on the DVOM to a known good ground. The resistance should be very high or over the limit (OL).
Torque converter clutch (TCC) solenoid – Check the resistance in the TCC solenoid and internal transmission wiring at the transmission case after removing the transmission harness plug (if applicable, some makes/models use a TCM bolted directly to the transmission case). Some makes/models use a transmission wire harness with the TCC solenoid and internal harness as a single unit. The DVOM should be set to the ohms scale with the positive lead and negative lead on the pins for the TCC power and control circuit. The resistance should be within the manufacturer’s specifications. If it is very high or over the limit (OL), remove the transmission oil pan to inspect the solenoid inside the transmission if possible. Check for voltage on the power side circuit of the TCC solenoid or at the wire harness connector at the TCM with the DVOM set to the volts scale. The positive lead should be at the wire being tested and the negative lead to a known good ground with the vehicle’s key on/engine off. Battery voltage should be present.
Transmission control module (TCM) – Since the torque converter clutch is only activated during certain driving conditions, it will be necessary to monitor the TCM with an advanced scan tool to determine if the TCM is commanding the TCC solenoid and what the actual feedback reading is at the TCM. The TCC solenoid is normally controlled by a duty cycle to engage a more comfortable torque converter clutch engagement.
To test if the TCM is actually sending the signal, a graphing multimeter set to duty cycle or a digital storage oscilloscope will be required as well. The positive lead is probed into the wiring harness plugged into the TCM, and the negative lead is connected to a known good ground. The duty cycle should be the same as being commanded by the TCM in the advanced scan tool reading. If the cycle stays at 0% or 100% or is intermittent, re-check connections. If all wiring and solenoid are OK, the TCM may be at fault.
