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P1744 Diagnostic Code on 1997 Ford Taurus After Transmission Replacement

Model: 1997 Ford Taurus Fault Code: P1744 Posted: 2006-06-13 13:02

After replacing the transmission in our 1997 Ford Taurus, we've started receiving the P1744 diagnostic code. The vehicle shifts smoothly through all gears and appears to operate normally, but the check engine light activates frequently during highway driving—especially after sustained use in higher gears. We have already replaced the wiring harness and confirmed that both the transmission and torque converter were replaced during the repair. Despite these changes, the P1744 code persists. The issue seems to be related to the Torque Converter Clutch (TCC) not engaging properly. The check engine light does not illuminate when driving in town but comes on consistently after a few kilometers on highways. We are concerned that this could indicate a failure in the transmission control module (TCM), an open circuit, or a faulty range sensor—common issues on older Ford transmissions. We’ve tried using an OBD-II scanner to turn off the code temporarily, but it returns quickly once we begin highway driving. This suggests the issue is not simply stored in memory and may be actively occurring during operation. We are seeking advice on how to properly diagnose whether the TCC is being commanded by the PCM or TCM, and what specific tests (such as stalling the engine in park) can help verify torque converter function. Could it be a faulty solenoid? A wiring issue? Or a problem with the overdrive switch or range sensor? Any guidance on next steps would be greatly appreciated.

Related fault codes

P1744

Comments (3)

Anonymous 2006-06-13 15:18

Was the torque converter replaced during the transmission rebuild? If so, it's possible that the Torque Converter Clutch (TCC) isn't engaging properly. A scan tool can often test the solenoid function—some tools allow you to command the TCC directly. To check this manually: start the engine and shift into Park. Then, with the vehicle stationary, turn on the ignition and try to stall the engine by pressing the accelerator fully while holding the brake. If the transmission doesn't lock up during this test, it may indicate a faulty solenoid or control circuit. This is a simple diagnostic that can help confirm whether the TCC is functioning correctly.

Anonymous 2006-06-14 08:15

Thank you for the detailed response. Yes, both the transmission and torque converter were replaced during the repair. The check engine light does not come on when driving in city traffic but activates consistently after a few kilometers on highways—especially when sustained higher gear usage occurs. I’m still unclear about how to perform the stalling test you described. Could you walk me through it step-by-step? For example, do I need to keep the brake pressed, what should the engine sound like during the stall, and is there a specific timing or duration required? We’re very concerned because after replacing both components, we expected full functionality. The car shifts smoothly, but the P1744 code keeps reappearing—especially on highways. We’ve turned off the code using an OBD-II scanner, but it returns immediately once we start highway driving. This makes us suspect that the issue is active and not just stored in memory. If the transmission repair is still under warranty, we should contact the service provider to have them address this issue—since a failure to lock up during gear shifts could potentially damage the new transmission over time.

Anonymous 2006-06-14 09:41

If the code returns so quickly after being cleared, it's unlikely that it's simply stored in memory—it’s likely an active fault. Given that the transmission repair is under warranty, we recommend contacting the service provider immediately to have them investigate. The issue may stem from a failure in the TCC command signal from the PCM or TCM, or an open circuit in the control wiring. A proper OBD-II scanner should be able to monitor the actual state of the TCC circuit during real-world driving—such as when shifting into overdrive or maintaining high-speed cruising. If your 1997 Ford Taurus has an overdrive switch (often located near the transmission), ensure it’s functioning correctly. Additionally, range sensors are known failure points on older Ford transmissions and should be checked if not already replaced. Failure to lock up during normal operation can lead to excessive wear or even damage to the new transmission. If the TCC isn’t engaging properly, the transmission could overheat or suffer mechanical stress. Always verify that the control signals are being sent correctly before continuing use. Good luck—please keep us updated on your progress.