P2743 — Transmission fluid temperature sensor circuit voltage too high

The transmission fluid temperature sensor is reporting a voltage higher than expected, indicating a possible electrical issue or sensor fault. This sensor helps the transmission control module monitor fluid temperature to protect the transmission from overheating.

Common causes

The cause is almost always one of a few things. Here they are — P2743 rarely comes from anything outside this list:

• Damaged or corroded sensor wiring or connector
• Faulty transmission fluid temperature sensor
• Poor electrical connection or short circuit
• Transmission control module malfunction

Where to start

In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:

1. Inspect and clean sensor wiring and connectors
2. Repair or replace damaged wiring as needed
3. Test and replace the transmission fluid temperature sensor
4. Check transmission fluid level and condition
5. Diagnose transmission control module if problem persists

That is what holds for P2743 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.