What Does P2743 Mean?
The transmission control module has detected an abnormally high voltage signal from transmission fluid temperature sensor B circuit. This typically indicates an open circuit, sensor failure, or short to voltage in the wiring harness.
Common Causes
35%
Transmission fluid temperature sensor B open circuit or internal failure
30%
Open circuit in wiring harness or broken wire between sensor and TCM
20%
Disconnected or loose sensor connector causing intermittent contact
10%
Short to voltage in sensor signal wire or damaged harness
5%
Failed transmission control module (TCM) internal reference circuit
Diagnostic Steps
1
Step 1: Visually inspect sensor connector for looseness, damage, or disconnection
2
Step 2: With sensor connected, backprobe sensor signal wire and measure voltage (typically 5V indicates open circuit)
3
Step 3: Disconnect sensor and measure resistance between sensor terminals (should be within spec, typically 1k-10k ohms depending on temperature)
4
Step 4: Check continuity of sensor signal and ground wires from connector to TCM
5
Step 5: If all wiring is intact, replace sensor and retest; if code persists, diagnose TCM
Estimated Repair Cost
$150 - $450
Parts + labor, varies by vehicle and location
The transmission control module has detected an abnormally high voltage signal from transmission fluid temperature sensor B circuit. This typically indicates an open circuit, sensor failure, or short to voltage in the wiring harness.
The most common cause of P2743 (Transmission Fluid Temperature Sensor "B" Circuit High) is: Transmission fluid temperature sensor B open circuit or internal failure
Typical repair costs for P2743 range from $150 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Transmission may shift erratically or enter fail-safe mode with limited gears available. Continued operation may cause overheating if actual fluid temperature cannot be monitored.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2743 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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