P0744

Schematic:

Diagnostic Chart:

The torque converter has an electronically controlled capacity clutch (ECCC). In the ECCC system, the pressure plate does not always fully lock to the torque cover. At certain speeds, the TCC lockup PC solenoid is precisely controlled to maintain a small amount of slippage between the engine and the transaxle, reducing driveline torsional disturbances. The transaxle control module (TCM) uses information from the output speed sensor (OSS) to determine if shudder is present by calculation of OSS frequency variance. The TCM monitors the OSS to detect shudder while the TCC is partially applied. If too much shudder is detected with the TCC partially applied, the TCM will then release the TCC, and monitor the OSS again for shudder. This allows the TCM to determine if the shudder is caused by the TCC system or by a rough road. DTC P0744 sets when the OSS indicates too much TCC shudder with the TCC partially applied, and no shudder with the TCC released.

DTC PARAMETERS
DTC P0744 set if the output speed sensor indicates TCC shudder

DTC P0744 is a type D DTC.

DIAGNOSTIC AIDS

IMPORTANT: If DTC P0722, P0727, P0733, P0734, P0735, P0966, P0967, P0982, P0983, or P1868 is set, diagnose that DTC first.

Use a Scan tool to monitor Transmission OSS while wiggling wires.

DTC P0744 can set due to:
^ Old transaxle fluid
^ Incorrect transaxle fluid level
^ Incorrect transaxle fluid type
^ Contaminated transaxle fluid
^ Intermittent open anywhere in the OSS circuit
^ Loose or damaged OSS
^ Electromagnetic interference (EMI) cause by high current carrying wiring routed near OSS sensor wiring
^ Shift solenoid 4 leaking or stuck open
^ TCC lockup PC solenoid stuck
^ Torque converter

If Shift Solenoid 4 stuck open, a 2.89 Gear Ratio in 3rd gear will result.

If the TCC lockup PC solenoid is stuck, harsh shifts between 1st, 2nd, and 3rd gears will result.

^ Shift Solenoid 4 resistance: 8.4-22.6 ohms
^ TCC lockup PC Solenoid resistance: 3.8-8.3 ohms

OSS resistance: Open