P2743 code meaning
Transmission Fluid Temperature Sensor B Circuit High
Powertrain system Generic code P27xx codes Check engine light
What P2743 means
P2743 is the counterpart of P2742: the sensor B signal is above its valid range. In GM's 2023/24 dual-clutch TCM the cooler temperature sensor must exceed 4745 mV for 500 ms, Type B; with an NTC thermistor fed from 5 V that points to a broken wire, an unplugged connector or a short to supply voltage, and the reading looks extremely cold. Ford uses P2743 as the out-of-window-high check of the TR9070 cooler-out sensor. Mitsubishi's 2009 Lancer Twin Clutch SST again reasons in temperature: 150 °C or more for 400 ms sets the code, and it advises checking the CAN bus first because bus faults can produce a false entry. Without B the module can no longer judge the cooler outflow and falls back on sensor A.
P2743 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 6 hours
- Clears after repairAfter a drive cycle
Symptoms of P2743
- Warning lamp or transmission message
- Scan tool shows sensor B extremely cold (GM, Ford) or extremely hot (Mitsubishi)
- Cooler control falls back on sensor A
Common causes of P2743
- Most likelyOpen circuit – broken lead or unplugged connector at sensor B
- PossibleSignal lead shorted to a voltage source
- Less likelyCAN fault or control unit with built-in sensor (Mitsubishi TC-SST)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Trans fluid temp sensor bWiring harness
What each part of P2743 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 7 | Area: transmission. |
| 43 | The exact fault in that area. |
What to do next
- Note P2743 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2743
What does P2743 mean?
P2743 means "Transmission Fluid Temperature Sensor B Circuit High". P2743 is the counterpart of P2742: the sensor B signal is above its valid range. It is a generic code, so it means the same on every make.
Is it safe to drive with P2743?
Drive gently and only to a workshop. With P2743 the car can go into limp mode (reduced power) to protect itself.
Will P2743 fail an emissions test?
P2743 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P2743 to fix?
Difficulty: medium. A typical repair takes 0.5 to 6 hours of work. This is a job for a workshop.
Will P2743 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.