Nissan Sentra P1605 Fault: No TCM Detected with O/D Light Flashing and Transmission Jerking
I own a 2000 Nissan Sentra GXE (CA model) with 117,000 miles. I knew there was an issue when I purchased it, but I thought a simple wiring fix would resolve the problem. Using my OBD-II scanner, I've consistently seen fault code P1605. My VIN is CA model-specific, and notably, this vehicle does not have a TCM (Transmission Control Module). After thoroughly inspecting all wiring harnesses and connections, I’ve replaced the battery, throttle position sensor (TPS), and several other components with no improvement. The only physical anomaly I've noticed is that liquid appears to have spilled onto the console, coating relays and connectors. As a result, the overdrive (O/D) light flashes continuously, and the automatic transmission jerks during shifts—never smoothly engaging into overdrive. This behavior strongly correlates with P1605, especially given the absence of a TCM in this model variant.
I found an earlier post discussing a different Nissan model that matches my symptoms: '99 Nissan Quest with codes P0105, P0325, P1605, P0446, P1400, and P1705. Report Post by supernet » Thu Jan 25, 2007 12:55 pm. This suggests that P1605 may be linked to transmission or control module issues, especially in models without a TCM. The presence of liquid damage on wiring and relays could also contribute to intermittent faults. I'm cross-referencing this with my own case to see if similar root causes exist.